diff --git "a/4NFST4oBgHgl3EQfZjjS/content/tmp_files/load_file.txt" "b/4NFST4oBgHgl3EQfZjjS/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/4NFST4oBgHgl3EQfZjjS/content/tmp_files/load_file.txt" @@ -0,0 +1,727 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf,len=726 +page_content='arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='13792v1 [math.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='FA] 31 Jan 2023 Linear extension operators for Sobolev spaces on uniform trees Charles Fefferman1 and Bo’az Klartag2 Dedicated in friendship to David Jerison Abstract Let 1 < p < ∞ and suppose that we are given a function f defined on the leaves of a weighted tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We would like to extend f to a function F defined on the entire tree, so as to minimize the weighted W 1,p-Sobolev norm of the extension.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' An easy situation is when p = 2, where the harmonic extension operator provides such a function F.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this note we record our analysis of the particular case of a uniform binary tree, which is a complete, finite, binary tree with weights that depend only on the distance from the root.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Neither the averaging operator nor the harmonic extension operator work here in general.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Nevertheless, we prove the existence of a linear extension operator whose norm is bounded by a constant depending solely on p.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This operator is a variant of the standard harmonic extension operator, and in fact it is harmonic extension with respect to a certain Markov kernel determined by p and by the weights.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 1 Introduction Consider a full binary tree of height N, whose set of vertices is denoted by V = N � k=0 {0, 1}k, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', the vertices are strings of zeroes and ones of length at most N.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For x ∈ {0, 1}k and ℓ ≤ k we write πℓ(x) ∈ {0, 1}ℓ for the prefix of x of length ℓ.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus for k ≥ 1, the parent of a vertex x ∈ {0, 1}k ⊆ V is the vertex πk−1(x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The set {0, 1}0 is a singleton whose unique element is denoted by ∅, the empty string, which is the root of the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The set of leaves of the tree is 1Department of Mathematics, Princeton University, Fine Hall, Washington Road, Princeton, New Jersey 08544, USA.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Email: cf@math.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='princeton.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='edu.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Supported by the Air Force Office of Scientific Research, grant number FA9950-18-1-0069 and the National Science Foundation (NSF), grant number DMS-1700180.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2Department of Mathematics, Weizmann Institute of Science, Rehovot 7610001, Israel.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Email: boaz.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='klartag@weizmann.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ac.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='il.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Supported by a grant from the Israel Science Foundation (ISF).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 1 {0, 1}N, and all other vertices in V are internal vertices.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A vertex x ∈ {0, 1}k is said to have depth d(x) = k, thus leaves have depth N and the root has depth 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The collections of bijections from V to V that preserve depth and parenthood relations form a group.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This group is referred to as the symmetry group of the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It has 22N−1 elements, and it is a 2-Sylow subgroup of the group of all permutations of the leaves.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The set E = N � k=1 {0, 1}k = V \\ {∅} is referred to as the set of edges of the tree, and the depth of an edge e ∈ {0, 1}k is d(e) = k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' That is, we think of e ∈ E as an undirected edge connecting the vertex whose string corresponds to e to its unique parent.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Each internal vertex other than the root is connected to three vertices, which are its parent and its two children.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Assume that we are given edge weights W1, W1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , WN > 0, where we view Wk as the weight of all edges of depth k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For 1 < p < ∞, the associated ˙W 1,p-seminorm is defined, for F : V → R, via ∥F∥ ˙W 1,p(V ) = \uf8eb \uf8ed N � k=1 Wk � x∈{0,1}k |F(x) − F(πk−1(x))|p \uf8f6 \uf8f8 1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (1) We write ∂V = {0, 1}N ⊆ V for the set of leaves of the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The trace of the ∥·∥ ˙W 1,p-seminorm is defined, for f : ∂V → R, via ∥f∥ ˙W 1,p(∂V ) = inf � ∥F∥ ˙W 1,p(V ) ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' F|∂V = f � , (2) i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', the infimum of the ˙W 1,p-seminorm over all extensions of f from the leaves to the entire tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We write RV for the collection of all functions f : V → R, and similarly R∂V is the collection of all functions f : ∂V → R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Our main result is the following: Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 1 < p < ∞ and let W1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , WN > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then there exists a linear operator H : R∂V → RV with the following properties: 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It is a linear extension operator, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', (Hf)(x) = f(x) for any x ∈ ∂V and any function f : ∂V → R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Its norm is bounded by a constant ¯Cp depending only on p, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', for any f : ∂V → R, ∥Hf∥ ˙W 1,p(V ) ≤ ¯Cp∥f∥ ˙W 1,p(∂V ).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2 In fact, we have the bound ¯Cp ≤ 4p1/pq1/q · � 1 + max{(p − 1)−1/p, (q − 1)−1/q} � ≤ C · max � 1 p − 1, 1 q − 1 � , (3) where q = p/(p − 1) and where C > 0 is a universal constant.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The proof of Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 is constructive, and the extension operator H that we construct is in fact a harmonic extension operator with respect to a certain random walk defined on the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' At each step the random walk jumps from a vertex to one of its neighbors, where of course the neighbors of a vertex are its parent and its children.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The Markov kernel corresponding to the random walk is invariant under the symmetries of the tree, thus the probability to move from a vertex to its neighbor depends only on the weights of the vertex and of its neighbor.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The Markov kernel of our random walk is determined by the following requirement: For any s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, the probability that a random walk starting at some vertex of depth s will reach a leaf before reaching a vertex of depth s − 1 equals qs = (2sWs)−1/(p−1) �N k=s(2kWk)−1/(p−1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (4) Thus the weights of our random walk typically depend on p ∈ (1, ∞), except for the case where Ws is proportional to 2−s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This seems inevitable.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Indeed, in some examples such as the 3rd example in Section 2 below, the linear extension operator H : R∂V → RV that corresponds to the parameter value p = p0, is not uniformly bounded for any p ∈ (1, ∞) \\ {p0}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' When p = 2, our random walk coincides with the usual random walk corresponding to the given weights on the edges of the binary tree, and thus in this case H is the standard harmonic extension operator (hence ¯Cp = 1 for p = 2).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' There is a certain range of weights where the averaging operator yields a uniformly bounded linear extension operator, as proven by Bj¨orn ×2, Gill and Shanmugalingam [1].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The averaging operator is the extension operator that assigns to each internal vertex v the average of the function values on the leaves of the subtree whose root is v.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This averaging operator seems natural also from the point of view of Whitney’s extension theory, see the work by Shvartsman [5] on Sobolev extension in W 1,p(Rn).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' However, there are examples of uniform binary trees where the averaging operator does not provide a uniformly bounded operator, such as the case where Wk = 2−k for all k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' What about non-uniform trees?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Suppose that the edge weights are arbitrary positive numbers (We)e∈E that are not necessarily determined by the depth of the edge.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' When p = 2, there is still a harmonic extension operator of norm one from ˙W 1,p(∂V ) to ˙W 1,p(V ).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' However, for p ̸= 2 the situation seems subtle.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We conjecture that in the general case of non-uniform tree weights there is no linear extension operator whose norm is bounded by a function of p alone.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This conjecture is closely related to questions about well-complemented subspaces of ℓn p that are beyond the scope of this note.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 3 In order to prove Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 we reformulate the problem in a way that brings us closer to analysis in ℓp-spaces.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For 1 < p < ∞, the associated Lp(E)-norm is defined, for f : E → R, via ∥f∥p = ∥f∥Lp(E) = \uf8eb \uf8ed N � k=1 Wk � x∈{0,1}k |f(x)|p \uf8f6 \uf8f8 1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (5) We think of a function f : E → R as the gradient of a function ˜f : V → R, uniquely determined up to an additive constant.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Given f : E → R we thus define a function ˜f : V → R as follows: For any x ∈ V other then the root, ˜f(x) = d(x) � i=1 f(πix), (6) while ˜f(x) = 0 if x = ∅ is the root.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The only property of ˜f that matters is that for all x ∈ E, f(x) = ˜f(x) − ˜f(πd(x)−1(x)).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We are interested in finding a linear operator T : Lp(E) → Lp(E), with a uniform bound on its operator norm, that has the following properties: 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator T takes the form Tf(x) = ˜T ˜f(x) − ˜T ˜f(πd(x)−1x) (7) for some linear operator ˜T : RV → RV .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' That is, ˜T takes functions on V to functions on V , and T is induces from ˜T via formula (7).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator ˜T is equivariant with respect to the tree symmetries and it satisfies ˜T(1) ≡ 1, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', it maps the constant function 1 to itself.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The function ˜Tg coincides with the function g on the leaves of the tree, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ( ˜Tg)|∂V = g|∂V for any g : V → R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The function ˜Tg is determined by the values of the function g on the leaves of the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator norm of ˜T with respect to the ˙W 1,p-seminorm equals to the operator norm of T with respect to the Lp(E)-norm.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Defining H(f|∂V ) = ˜Tf, Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 may thus be reformulated as follows: Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 1 < p < ∞ and let W1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , WN > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then there exists a linear operator T : Lp(E) → Lp(E) with the above properties, whose operator norm is at most a certain constant ¯Cp depending only on p.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In fact, we have the bound (3) for the constant ¯Cp.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 4 The proof of Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 occupies the next three sections.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In Section 2 we discuss invariant random walks on a full binary tree and describe the corresponding harmonic extension operator.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In Section 3 we deal with the problem of bounding the norm of this operator, and use the sym- metries of the problem in order to reduce it to a one-dimensional question.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This one-dimensional question is then answered in Section 4 using the Muckenhoupt criterion [4].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' When analyzing the binary tree we use the following notation: We write dlca(x, y) for the length of the maximal prefix shared by the strings x ∈ {0, 1}k and y ∈ {0, 1}ℓ, while lca(x, y) is the maximal prefix itself.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus for two vertices x, y ∈ V , their least common ancestor is lca(x, y) ∈ V and its depth is dlca(x, y) ∈ {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Note that for any x ∈ E and ω ∈ ∂V , dlca(πd(x)−1x, ω) = min{d(x) − 1, dlca(x, ω)}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (8) Acknowledgements.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We would like to thank Jacob Carruth, Arie Israel, Anna Skorobogatova and Ignacio Uriarte-Tuero for helpful conversations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This research was conducted while BK was visiting Princeton University’s Department of Mathematics;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' he is grateful for their gracious hospitality.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2 Invariant random walks A Markov chain on V is a sequence of random variables R1, R2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ∈ V such that the distribution of Ri+1 conditioned on R1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , Ri is the same as its distribution conditioned on Ri.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A Markov chain is time-homogeneous if for any x, y ∈ V , the probability that Ri+1 = x conditioned on the event Ri = y does not depend on i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A random walk on V is a time-homogeneous Markov chain R1, R2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ∈ V such that Ri+1 is a neighbor of Ri with probability one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We say that the random walk is invariant if the probability to jump from a vertex x to a vertex y depends only on the depths d(x) and d(y).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Our random walk will be invariant, and it will stop when it reaches a leaf, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', we have the stopping time τ = min{i ≥ 1 ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Ri is a leaf}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For s ≥ 1 we define qs to be the probability of the following event: Assuming that R1 is a vertex of depth s, the event is that Ri will remain at the subtree whose root is R1 for all 1 ≤ i ≤ τ.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Equivalently, define Xi = d(Ri) ∈ {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then X1, X2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ∈ {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} is a random walk, since |Xi+1 − Xi| = 1 for all i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Furthermore, qs = P(∀1 ≤ i ≤ τ, Xi ≥ s | X1 = s).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (9) Clearly q0 = qN = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (10) For r, s ∈ {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} with r ≤ s we set ps,r = P(min{Xi ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' i ≤ τ} = r | X1 = s).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 5 That is, the number ps,r is the probability that r is the minimal node that the walker visits when starting from node s, before reaching the terminal node N.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Clearly �s r=0 ps,r = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For 0 ≤ r ≤ s ≤ N − 1, ps,r = qr · s � k=r+1 (1 − qk) (11) where an empty product equals one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Moreover, pN,r = δrN, where δrN is the Kronecker delta.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The expression on the right-hand side of (11) is the probability to ever reach s − 1 when starting from X1 = s, and from s − 1 to ever reach s − 2, etc.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' until we finally reach r, yet from r we require to never reach r − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Alternatively, when 0 ≤ r ≤ s, s ≥ 1 we have the recurrence relation ps,r = qsδs,r + (1 − qs) · ps−1,r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (12) This recurrence relation leads to another proof of (11).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Suppose that our random walk R1, R2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ∈ V begins at a vertex R1 = x with d(x) = s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Consider a leaf y ∈ ∂V with dlca(x, y) = r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' What is the probability that our random walk will reach the leaf y?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We claim that this probability is bs,r := P(Rτ = y) = r � k=0 2k−Nps,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (13) Indeed, conditioning on the value of k = mini≤τ d(Ri), by symmetry we know that Rτ is dis- tributed uniformly among the 2N−k leaf-descendants of the vertex πk(x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' When k ≤ r, exactly one of these leaf-descendants is the leaf y, since the vertex of minimal depth that (Ri) visits must be the vertex πk(x), which is a prefix of y as k ≤ r = dlca(x, y).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence the probability that Rτ = y, conditioning on the value of k, equals to 1/2N−k when k ≤ r and it vanishes other- wise.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By using the definition of ps,k and the complete probability formula, we obtain (13).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The harmonic extension operator associated with our invariant random walk is given by ˜Tg(x) = � ω∈{0,1}N bd(x),dlca(x,ω) · g(ω) (x ∈ V ).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (14) The operator T is induced from ˜T via formula (7) above.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Requirements 1,.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='..' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=',4 from Section 1 are clearly satisfied.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We stipulate that the collection of descendants of a vertex x ∈ V , denoted by D(x) ⊆ V , includes the vertex x itself.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Abbreviate a ∧ b = min{a, b} and a ∨ b = max{a, b}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator T takes the form Tf(x) = � y∈E K(x, y)f(y), (15) where the kernel K is described next.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 6 Proposition 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let x, y ∈ E and denote s = d(x), t = d(y), r = dlca(x, y).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then the following hold: If x ̸∈ D(y) and y ̸∈ D(x), then r ≤ s ∧ t − 1 and K(x, y) = −qs · 2−t · r � k=0 2kps−1,k ≤ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (16) Otherwise, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', if y ∈ D(x) or if x ∈ D(y) then r = s ∧ t and K(x, y) = qs · 2−t · r−1 � k=0 (2r − 2k)ps−1,k ≥ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (17) Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By (7) and (14) we have, for any x ∈ E, Tf(x) = ˜T ˜f(x) − ˜T ˜f(πd(x)−1x) = � ω∈{0,1}N bd(x),dlca(x,ω) ˜f(ω) − � ω∈{0,1}N bd(x)−1,dlca(πd(x)−1x,ω) ˜f(ω) = � ω∈{0,1}N ad(x),dlca(x,w) ˜f(ω) (18) where for any 0 ≤ r ≤ s, by (8) and (13), as,r = bs,r − bs−1,min{s−1,r} = r � k=0 2k−Nps,k − min{s−1,r} � k=0 2k−Nps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (19) Hence, by (6) and (18), Tf(x) = � ω∈{0,1}N ad(x),dlca(x,ω) N � i=1 f(πiω) = � y∈E \uf8ee \uf8f0 � ω∈{0,1}N;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='πd(y)ω=y ad(x),dlca(x,ω) \uf8f9 \uf8fb f(y) = � y∈E K(x, y)f(y), where the kernel K of the operator T satisfies, for any x, y ∈ E, K(x, y) = � ω∈{0,1}N ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='πd(y)ω=y ad(x),dlca(x,ω).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (20) Fix x, y ∈ E with s = d(x), t = d(y) and r = dlca(x, y).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let us consider first the case where x is not a descendant of y.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This means that the prefix of y that is shared by x, is not the entire string y.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence for any ω ∈ {0, 1}N with πd(y)ω = y we have dlca(x, ω) = dlca(x, y) ≤ d(y) − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Therefore, from (20) and (19), K(x, y) = 2N−d(y)ad(x),dlca(x,y) = 2N−t � bs,r − bs−1,(s−1)∧r � = r � k=0 2k−tps,k − (s−1)∧r � k=0 2k−tps−1,k, 7 as bs,r = �r k=0 2k−Nps,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since ps,s = qs, we have K(x, y) = δrs2s−tqs + (s−1)∧r � k=0 2k−t [ps,k − ps−1,k] = qs · \uf8ee \uf8f0δrs2s−t − (s−1)∧r � k=0 2k−tps−1,k \uf8f9 \uf8fb , (21) where we used the relation (12), which implies that when k ≤ s − 1, ps,k − ps−1,k = −qs · ps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (22) We may now prove the conclusion of the proposition in the case where x ̸∈ D(y) and y ̸∈ D(x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Indeed, in this case r ≤ s ∧ t − 1 and formula (21) applies.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since δrs = 0 in this case, we deduce formula (16) from (21).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The next case we consider is the case where r = s ≤ t − 1, or equivalently, where y ∈ D(x) \\ {x}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus x ̸∈ D(y) and formula (21) applies.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recalling that �s−1 k=0 ps−1,k = 1 we obtain from (21) that K(x, y) = qs · s−1 � k=0 (2s−t − 2k−t)ps−1,k = qs · 2−t · s−1 � k=0 (2r − 2k)ps−1,k, proving formula (17) in the case y ∈ D(x) \\ {x}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We move on to the case where x ∈ D(y) \\ {y}, thus dlca(x, y) = t ≤ s − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this case, by applying (20), (19), (13) and then (22), K(x, y) = � ω∈{0,1}N ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='πd(y)ω=y ad(x),' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='dlca(x,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ω) = 2N−d(x)ad(x),' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='d(x) + d(x)−1 � k=d(y) 2N−k−1ad(x),' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k = 2N−sas,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='s + s−1 � k=t 2N−k−1as,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k = 2N−s(bs,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='s − bs−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='s−1) + s−1 � k=t 2N−k−1(bs,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k − bs−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k) = 2N−s � s � k=0 2k−Nps,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k − s−1 � k=0 2k−Nps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k � + s−1 � k=t 2N−k−1 k � ℓ=0 2ℓ−N(ps,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ℓ − ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ℓ) = qs − qs s−1 � k=0 2k−sps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k − qs s−1 � ℓ=0 s−1 � k=ℓ∨t 2ℓ−k−1ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ℓ = qs � 1 − s−1 � k=0 2k−sps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k − s−1 � ℓ=0 [2ℓ−ℓ∨t − 2ℓ−s]ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='ℓ � = qs � 1 − s−1 � k=0 2k−k∨tps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k � = qs · � 1 − t−1 � k=0 2k−tps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k − s−1 � k=t ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k � = qs · t−1 � k=0 (1 − 2k−t)ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k = qs · 2−t · t−1 � k=0 (2t − 2k)ps−1,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 8 Since r = t in this case, we have proved formula (17) in the case where y ∈ D(x) \\ {x}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Finally, the last case that remains is when x = y.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this case r = s = t and K(x, y) = � ω∈{0,1}N;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='πd(y)ω=y ad(x),dlca(x,ω) = 2N−d(x)ad(x),d(x) = 2N−sas,s = 2N−s(bs,s − bs−1,s−1) = 2N−s � s � k=0 2k−Nps,k − s−1 � k=0 2k−Nps−1,k � = qs − qs s−1 � k=0 2k−sps−1,k = qs · s−1 � k=0 (1 − 2k−s)ps−1,k, completing the proof of formula (17).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Some examples.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The simplest example is when qs = 1 for all s ≥ 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this case the operator ˜T is the familiar averaging operator.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' That is, the extension operator ˜T is the operator that assigns to each vertex the average of the values at the leaves of its subtree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this case ps,r = δs,r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Consider the case where the invariant random walk is such that Xi := d(Ri) is a symmetric random walk on {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N}, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', the probability to jump from i to i + 1 is exactly 1/2 for i = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recall that qs is the probability to never leave the subtree when starting at a vertex of depth s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We claim that in this example, for s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, qs = 1 N − s + 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (23) Indeed, the function f(i) = i is harmonic on {0, 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} and hence f(Xi) is a mar- tingale.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus for any stopping time ˜τ we have f(X1) = Ef(X˜τ).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We pick the stopping time ˜τ = min{ i;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Xi ∈ {s − 1, N} } and obtain (23) since N · qs + (s − 1) · (1 − qs) = s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Next we use Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 and find a formula for ps,r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since formula (23) is valid for any s ≥ 1, we conclude that for any r ≥ 0 and s ≥ r + 1, s� k=r+1 (1 − qk) = s� k=r+1 N − k N − k + 1 = N − s N − r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (24) 9 Formula (24) is actually valid for any 0 ≤ r ≤ s, since an empty product equals one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recall that q0 = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We thus conclude from Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 that for s = 0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1, ps,r = N − s N − r · � 1 r = 0 1 N−r+1 1 ≤ r ≤ s while pN,r = δN,r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 0 < δ < 1, and consider the case where (Xi) is a random walk on {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} such that the probability to jump from k to k + 1 equals 1/2 if k < N − 1, and it equals δ if k = N − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A harmonic function here is f(k) = � k k ≤ N − 1 N − 2 + 1/δ k = N Therefore, for s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1, (N − 2 + 1/δ) · qs + (s − 1)(1 − qs) = s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus q0 = qN = 1 while for s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1, qs = 1 N − s + 1/δ − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence for any s ≤ N − 1 and r ≤ s − 1, s � k=r+1 (1 − qk) = s � k=r+1 N − k + δ−1 − 2 N − k + δ−1 − 1 = N − s + δ−1 − 2 N − r + δ−1 − 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We conclude from Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 that for s = 0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1 and 0 ≤ r ≤ s, ps,r = qr · s� k=r+1 (1 − qk) = N − s + δ−1 − 2 N − r + δ−1 − 2 · � 1 r = 0 1 N−r+1/δ−1 1 ≤ r ≤ s while pN,r = δN,r.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We conclude this section with the following: Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For any numbers q1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , qN−1 ∈ (0, 1) there exists a random walk X1, X2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' ∈ {0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} satisfying (9) with τ = min{i ≥ 1 ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Xi = N} for s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Write xk for the probability that the random walk jumps from k to k + 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then for s = 0, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N − 1, qs = xs(qs+1 + (1 − qs+1)xs), (25) where we set q0 = qN = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We claim that xs ∈ [0, 1] is determined by equation (25).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Indeed, the right-hand side of (25) is a continuous, increasing function of xs in the interval [0, 1], that maps this interval to itself.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 10 3 The ancestral and non-ancestral parts of the kernel We need to bound the operator norm in Lp(E) of the operator T whose kernel is described in Proposition 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let us consider first the non-ancestral part of the operator, given by the kernel K0(x, y) = K(x, y) · 1{x̸∈D(y),y̸∈D(x)} = −1{r≤s∧t−1} · qs · 2−t · r � k=0 2kps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (26) Here as usual s = d(x), t = d(y) and r = dlca(x, y).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Write T0 : Lp(E) → Lp(E) for the operator whose kernel is K0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A function f : E → R is invariant under the symmetries of the tree, or invariant in short, if it takes the form f(x) = F(d(x)) for some function F : {1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} → R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator T0 is equivariant under the symmetries of the tree.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Therefore, if f(x) = F(d(x)) is an invariant function, then so is T0f.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In fact, in the case where f(x) = F(d(x)) we can write T0f(x) = N � t=1 L0(d(x), t)F(t) (27) for a certain kernel L0(s, t) defined for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Lemma 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, L0(s, t) = −qs · m−1 � k=0 (1 − 2k−m)ps−1,k ≤ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let r ≤ min{t, s} − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A moment of reflection reveals that for x ∈ E with d(x) = s, n(t;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' s, r) := #{y ∈ E ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' d(y) = t, dlca(x, y) = r} = 2t−r−1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By (26), (27) and the definition of T0, for any x ∈ E with d(x) = s, L0(s, t) = � y∈E;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='d(y)=t K0(x, y) = − t∧s−1 � r=0 n(t;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' s, r) · qs · 2−t · r � k=0 2kps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denote m = s ∧ t.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, L0(s, t) = −qs · t∧s−1 � r=0 r � k=0 2k−r−1ps−1,k = −qs · m−1 � k=0 m−1 � r=k 2k−r−1ps−1,k = −qs · m−1 � k=0 (1 − 2k−m)ps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 11 Write ΩN = {1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N} and for F : ΩN → R define ∥F∥p = ∥F∥Lp(ΩN) = � N � k=1 2k · Wk · |F(k)|p �1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (28) Observe that ∥f∥Lp(E) = ∥F∥p if f(x) = F(d(x)).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let S0F(s) = N � t=1 L0(s, t)F(t) so that by (27), T0(F ◦ d) = (S0F) ◦ d.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (29) For f, g : E → R we consider the scalar product ⟨f, g⟩ = � x∈E Wd(x)f(x)g(x) while for F, G : ΩN → R we set ⟨F, G⟩ := ⟨F ◦ d, G ◦ d⟩ = N � k=1 2kWkF(k)G(k).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The adjoint operators T ∗ 0 and S∗ 0 are defined with respect to these scalar products.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The follow- ing lemma is probably well-known to experts (see, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', Howard and Schep [2] for a related argument), and its proof is provided for completeness.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Lemma 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 1 < p < ∞.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then the norm of the operator T0 : Lp(E) → Lp(E) is attained at an invariant, non-negative function f, and it equals to the norm of the operator S0 : Lp(Ωn) → Lp(Ωn).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denote momentarily T = −T0 and S = −S0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By Lemma 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 the kernel −L0 of the operator S is non-negative, and by (26) the kernel of the operator T is non-negative as well.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By approximation, we may assume that these two kernels are strictly positive, while keeping condition (29), thus T (F ◦ d) = (SF) ◦ d.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (30) We deduce that T ∗(F ◦ d) = (S∗F) ◦ d.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By compactness, sup 0̸≡F ∈Lp(ΩN ) ∥SF∥p ∥F∥p is attained at some function F.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since the kernel of S is non-negative, we may assume that the extremal function F is non-negative.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By the Lagrange multipliers theorem, the function F satisfies a certain eigenvalue equation, and in fact there exists λ ∈ R such that S∗(SF)p−1 = λF p−1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (31) 12 Since the kernel of S is positive and F is non-negative and not identically zero, it follows from (31) that F is actually positive.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The norm of the operator S : Lp(Ωn) → Lp(Ωn) equals λ1/p > 0, since ∥SF∥p p = ⟨(SF)p−1, SF⟩ = ⟨S∗(SF)p−1, F⟩ = λ⟨F p−1, F⟩ = λ∥F∥p p.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denoting f = F ◦ d, we find from (30) that f is a positive invariant function satisfying T ∗(T f)p−1 = λf p−1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since the kernel of T is non-negative, we have the pointwise H¨older inequality T (uv) ≤ T (up)1/p · T (vq)1/q, valid for any non-negative functions u, v ∈ Lp(E), where q = p/(p − 1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator T has a non-negative kernel, and hence its norm is attained at a non-negative function u ∈ Lp(E).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By the pointwise H¨older inequality, (T u)p ≤ T (upf −p/q) · (T f)p/q = T (upf 1−p) · (T f)p−1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Therefore, ∥T u∥p Lp(E) ≤ ⟨T (upf 1−p), (T f)p−1⟩ = ⟨upf 1−p, T ∗(T f)p−1⟩ = λ⟨upf 1−p, f p−1⟩ = λ∥u∥p Lp(E).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus the norm of T : Lp(E) → Lp(E) is at most λ1/p, which is the norm of S : Lp(ΩN) → Lp(ΩN).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The two norms must therefore be equal, since the operator S is equivalent to the restriction of T to the space of invariant functions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We move on to the ancestral part of the operator, which according to Proposition 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 is given by K1(x, y) = K(x, y) − K0(x, y) = 1{r=s∧t} · qs · 2−t · r−1 � k=0 (2r − 2k)ps−1,k ≥ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (32) Write T1 for the operator whose kernel is K1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' As before, for an invariant function f(x) = F(d(x)) we may write T1f(x) = N � t=1 L1(d(x), t)F(t) (33) for a certain kernel L1(s, t) defined for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We also write S1F(s) = N � t=1 L1(s, t)F(t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It is possible to use formula (7) for the operator T and the definition (14) of the harmonic exten- sion operator ˜T and deduce that S0 + S1 ≡ 0, (34) essentially because the only invariant, harmonic function on the vertices of the tree is the constant function.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' An alternative, more direct proof of (34) is provided in the following: 13 Lemma 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 1 < p < ∞.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then the norm of the operator T1 : Lp(E) → Lp(E) is equal to the norm of S1 : Lp(Ωn) → Lp(Ωn).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Additionally, for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N with m = s ∧ t we have L1(s, t) = qs · m−1 � k=0 (1 − 2k−m)ps−1,k = −L0(s, t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The first assertion of the lemma follows from fact that the kernel of T1 is non-negative and invariant under the symmetries of the tree, as in Lemma 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For the second part, let s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N and denote m = s ∧ t.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We claim that for x ∈ E with d(x) = s, n(t;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' s, m) := #{y ∈ E ;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' d(y) = t, dlca(x, y) = m} = max{1, 2t−s}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (35) Indeed, assume first that t ≥ s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' How many y’s are there with d(y) = t and dlca(x, y) = m?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since m = s, the answer is 2t−s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Next, if s ≥ t, then the number of such y’s is one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This proves (35).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Therefore, L1(s, t) = � y∈E;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='d(y)=t K1(x, y) = n(t;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' s, m) · qs · 2−t · m−1 � k=0 (2m − 2k)ps−1,k = max{2−t, 2−s} · qs · m−1 � k=0 (2m − 2k)ps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' = 2−m · qs · m−1 � k=0 (2m − 2k)ps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We have ∥T∥Lp(E)→Lp(E) ≤ 2∥S0∥Lp(ΩN)→Lp(ΩN).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This follows from the fact that T = T0 + T1 together with the facts that ∥T0∥ = ∥S0∥ and ∥T1∥ = ∥S1∥ while S1 = −S0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In view of Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4, we are interested in bounds for the norm of the operator S = −S0 = S1 : Lp(ΩN) → Lp(ΩN) whose non-negative kernel is L(s, t) = qs · s∧t−1 � k=0 (1 − 2k−s∧t)ps−1,k ≤ qs · s∧t−1 � k=0 ps−1,k.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (36) 14 From Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 we know that ps,r = qr · �s k=r+1(1 − qk) for s ≤ N − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' A little exercise in probability shows that for any 1 ≤ m ≤ s ≤ N, m−1 � k=0 ps−1,k = s−1 � k=m (1 − qk).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (37) Alternatively, (37) holds true for m = 0 as q0 = 1, and it may be proven by induction on m since ps−1,m + s−1 � k=m (1 − qk) = qm · s−1 � k=m+1 (1 − qk) + s−1 � k=m (1 − qk) = s� k=m+1 (1 − qk).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From (36) and (37) we thus obtain Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, with m = min{s, t}, 0 ≤ L(s, t) ≤ qs s−1 � k=m (1 − qk), where an empty product equals one.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Some examples (parallel to the ones discussed in Section 2).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For the averaging operator, where qs = 1 and ps,r = δs,r, we have L(s, t) = −1 2 · 1{s≤t}, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', this is the matrix whose entries equal 0 below the diagonal and −1/2 on and above the diagonal.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This is a rather simple matrix, and it is bounded with respect to the weighted Lp-norm for quite a few sequences of weights.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For the symmetric random walk matrix, we have q0 = 1 while for 1 ≤ s ≤ N, qs = 1 N − s + 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence in view of Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5, with m = min{s, t}, 0 ≤ L(s, t) ≤ 1 N − s + 1 s−1 � k=m N − k N − k + 1 = 1 N − m + 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In the case where qs = 1 N − s + 1/δ − 1 for some 0 < δ < 1, we have 0 ≤ L(s, t) ≤ 1 N − s + 1/δ − 1 s−1 � k=m N − k + 1/δ − 2 N − k + 1/δ − 1 = 1 N − m + 1/δ − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 15 All that remains is to bound the Lp(ΩN)-norm of the operator whose kernel is discussed in Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recall from Lemma 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3 that we have the freedom to choose the parameters q1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , qN−1 ∈ (0, 1) as we please.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' How should we choose these parameters?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since L(N, t) ≤ �N−1 k=t (1−qk) and we are looking for upper bounds for the norm, the qs should not be too tiny.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' On the other hand, L(s, t) ≤ qs for s ≤ N − 1 and hence it is beneficial to choose qs rather small.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We would therefore need some balance for the qs, which is the subject of the next section.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 4 One-dimensional analysis Let 1 < p < ∞.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It will be slightly more convenient to denote K(s, t) = L(N + 1 − s, N + 1 − t) and Qs = qN+1−s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recalling from (10) that qN = 1, we see that Q1 = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5 we know that for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, K(s, t) = L(N + 1 − s, N + 1 − t) ≤ qN+1−s N−s � k=N+1−max{s,t} (1 − qk) = Qs max{s,t} � k=s+1 (1 − Qk).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5 we know that L ≥ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Consequently, for s, t = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, 0 ≤ K(s, t) ≤ � Qs t ≤ s Qs · �t k=s+1(1 − Qk) t ≥ s + 1 (38) Recall that we are given edge weights W1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , WN > 0, and that the associated Lp(E)-norm is given by (5).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denote ws := 2N+1−s · WN+1−s > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Consider the weighted ℓp-norm ∥f∥p,w = � N � k=1 wk|f(k)|p �1/p (39) and the operator T whose kernel is K(s, t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We are allowed to choose the weights q1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , qN−1 ∈ (0, 1) as we please, or equivalently, we have the freedom to determine Q2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , QN ∈ (0, 1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We must keep Q1 = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Based on considerations related to the Muckenhoupt criterion discussed below, we set Qs = w−1/(p−1) s �s k=1 w−1/(p−1) k .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (40) It is clear that Q1 = 1 and that Qs ∈ (0, 1) for all s ≥ 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Recall that q = p/(p − 1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 16 Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In order to prove Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2, it suffices to show that the operator norm of T with respect to the ∥ · ∥p,w-norm is bounded by a constant ˆCp > 0 depending only on p, where in fact ˆCp ≤ 2p1/pq1/q · � 1 + max{(p − 1)−1/p, (q − 1)−1/q} � .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (41) Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In view of Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4, it suffices to bound the operator norm of −S0, whose kernel is L, with respect to the Lp(ΩN)-norm defined in (28).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Under the transformation s �→ N + 1 − s the operator −S0 whose kernel is L transforms to the operator T whose kernel is K.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The Lp(ΩN)- norm from (28) transforms to the ∥·∥p,w-norm defined in (39).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 would follow once we obtain the bound (41), where ¯Cp ≤ 2 ˆCp by Corollary 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The remainder of this section is devoted to the proof of the following: Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The operator norm of T with respect to the norm (39) is bounded by a number ˆCp depending only on p ∈ (1, ∞).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In fact, we have the bound (41) for the constant ˆCp.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Our main tool in the proof of Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 is the Muckenhoupt criterion [4], which is an indispensable tool for proving one-dimensional inequalities of Poincar´e-Sobolev type.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For the reader’s convenience, we include here a statement and a proof of a straightforward modification of the Muckenhoupt criterion, with sums in place of integrals: Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (Muckenhoupt) Let 1 < p < ∞ and write ΩN = {1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let U, V : ΩN → (0, ∞) and let A > 0 be such that for all r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � N � k=r |U(k)|p �1/p ≤ A � r � k=1 |V (k)|−q �−1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (42) Then for any function f : ΩN → R, � N � k=1 �����U(k) k � ℓ=1 f(ℓ) ����� p�1/p ≤ CpA � N � k=1 |V (k)f(k)|p �1/p , (43) with Cp = p1/pq1/q.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By continuity, the analog of Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3 for p = 1, ∞ holds true with C1 = C∞ = 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We remark that as in [4], this criterion is tight, in the sense that the infimum over all A > 0 satisfying (42) is equivalent to the best constant in inequality (43).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For the proof of Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3 we require the following: 17 Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For α1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , αN > 0 and r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, r � k=1 αk � k � ℓ=1 αℓ �−1/p ≤ q · � r � k=1 αk �1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (44) Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We will use the simple inequality (a + b)1/q − a1/q ≥ b · min ξ∈(a,a+b) ξ1/q−1 q = 1 q(a + b)1/q−1 · b, (45) valid for any a, b ≥ 0 with a + b > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From (45), for k = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � k � ℓ=1 αℓ �1/q − �k−1 � ℓ=1 αℓ �1/q ≥ 1 q · αk · � k � ℓ=1 αℓ �1/q−1 , where an empty sum equals zero.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By summing this for k = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , r we obtain (44).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof of Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3 (Muckenhoupt).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By the H¨older inequality, for any function f : ΩN → R and weights h : ΩN → (0, ∞), N � k=1 �����U(k) k � ℓ=1 f(ℓ) ����� p ≤ N � k=1 Up(k) · k � ℓ=1 |f(ℓ)V (ℓ)h(ℓ)|p · � k � j=1 |V (j)h(j)|−q �p/q = N � ℓ=1 |f(ℓ)V (ℓ)h(ℓ)|p N � k=ℓ Up(k) � k � j=1 |V (j)h(j)|−q �p/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (46) Set h(k) = ��k ℓ=1 V (ℓ)−q�1/(pq) .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By applying Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4 with αk = V (k)−q we obtain r � k=1 |V (k)h(k)|−q = r � k=1 αk � k � ℓ=1 αℓ �−1/p ≤ q · � r � k=1 αk �1/q = q · � r � k=1 V (k)−q �1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Hence for any f : ΩN → R, the expression in (46) is at most qp/q · N � ℓ=1 |f(ℓ)V (ℓ)h(ℓ)|p N � k=ℓ Up(k) � k � j=1 |V (j)|−q �p/q2 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (47) By applying (42) and then Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='4 with αk = Up(N + 1 − k) and with p ∈ (1, ∞) playing the rˆole of q ∈ (1, ∞), we see that N � k=ℓ |U(k)|p � k � j=1 |V (j)|−q �p/q2 ≤ Ap/q N � k=ℓ |U(k)|p � N � j=k |U(j)|p �−1/q = Ap/q N+1−ℓ � k=1 αk � k � j=1 αj �−1/q ≤ p · Ap/q �N+1−ℓ � k=1 αk �1/p = p · Ap/q � N � k=ℓ Up(k) �1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 18 Hence the expression in (47) is at most p · (qA)p/q · N � ℓ=1 |f(ℓ)V (ℓ)h(ℓ)|p · � N � k=ℓ Up(k) �1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Applying (42) again we bound the last expression from above by p · (qA)p/q · A · N � ℓ=1 |f(ℓ)V (ℓ)h(ℓ)|p · � ℓ � k=1 V −q(k) �−1/q = pqp/qAp N � ℓ=1 |f(ℓ)V (ℓ)|p, completing the proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Corollary 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let 1 < p < ∞ and ΩN = {1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let U, V : ΩN → (0, ∞) and let A > 0 be such that for all r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � r � k=1 |U(k)|p �1/p ≤ A � N � k=r |V (k)|−q �−1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (48) Then for any f : ΩN → R, � N � k=1 �����U(k) N � ℓ=k f(ℓ) ����� p�1/p ≤ CpA � N � k=1 |V (k)f(k)|p �1/p , (49) with Cp = p1/pq1/q.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denote ˜U(k) = U(N + 1 − k) and ˜V (k) = V (N + 1 − k).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then from (48), for all r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � N � k=r | ˜U(k)|p �1/p ≤ A � r � k=1 | ˜V (k)|−q �−1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3, this implies that for any g : ΩN → R, denoting f(r) = g(N + 1 − r), � N � k=1 ����� ˜U(k) k � ℓ=1 f(N + 1 − ℓ) ����� p�1/p ≤ CpA � N � k=1 | ˜V (k)f(N + 1 − k)|p �1/p , or equivalently, � N � k=1 ����� ˜U(N + 1 − k) N � ℓ=k f(ℓ) ����� p�1/p ≤ CpA � N � k=1 | ˜V (N + 1 − k)f(k)|p �1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This implies (49).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 19 Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='6.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For f : Ωn → R and s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N denote T0f(s) = Qs s � t=1 f(t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then the operator norm of T0 with respect to the norm ∥ · ∥p,w defined in (39) is bounded by a number ˜Cp depending only on p ∈ (1, ∞).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In fact, ˜Cp ≤ 21/pp1/pq1/q · max{1, (p − 1)−1/p}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The proof of Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='6 requires the following: Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='7.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For any α1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , αN > 0 and r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, N � k=r αk � k � ℓ=1 αℓ �−p ≤ 2 min{1, p − 1} · � r � k=1 αk �−p+1 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (50) Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We use the inequality (p − 1) · b(a + b)−p ≤ a−p+1 − (a + b)−p+1, which is valid for any a, b > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then for k = 2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, (p − 1) · αk � k � ℓ=1 αℓ �−p ≤ �k−1 � ℓ=1 αℓ �−p+1 − � k � ℓ=1 αℓ �−p+1 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By summing this for k = r + 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N we obtain (p − 1) · N � k=r+1 αk � k � ℓ=1 αℓ �−p ≤ � r � k=1 αk �−p+1 − � N � ℓ=1 αℓ �−p+1 ≤ � r � k=1 αk �−p+1 , where an empty sum equals zero.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We conclude (50) by summing this with the trivial inequality min{1, p − 1} · αr � r � ℓ=1 αℓ �−p ≤ � r � k=1 αk �−p+1 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof of Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='6.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Define U(k) = w1/p k Qk and V (k) = w1/p k .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Let us verify the condition of the Muckenhoupt criterion.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We need to find A > 0 such that for all r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N inequality (42) holds true, that is, N � k=r wkQp k ≤ Ap � r � k=1 w−q/p k �−p/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (51) 20 Recall that p/q = p − 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From the definition (40) of Qk, we need N � k=r w−1/(p−1) k � k � ℓ=1 w−1/(p−1) ℓ �−p ≤ Ap � r � k=1 w−1/(p−1) k �−(p−1) .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Setting αk = w−1/(p−1) k and using Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='7, we see that (51) holds true with A = 21/p · max{1, (p − 1)−1/p}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From Theorem 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='3 we thus conclude that for any f : ΩN → R, � N � k=1 wk �����Qk k � ℓ=1 f(ℓ) ����� p�1/p ≤ p1/pq1/qA · � N � k=1 wk|f(k)|p �1/p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This implies the required bound for the operator norm of f.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='8.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For f : Ωn → R and s = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N denote T1f(s) = N � t=s+1 � Qs t� k=s+1 (1 − Qk) � f(t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Then the operator norm of T1 with respect to the norm ∥ · ∥p,w defined in (39) is bounded by 21/qp1/pq1/q · max{1, (q − 1)−1/q}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denote αk = w−1/(p−1) k and recall from (40) that Qk = αk/ �k ℓ=1 αℓ.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' We claim that for any t ≥ s + 1, Qs t� k=s+1 (1 − Qk) = αs �t k=1 αk .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (52) Indeed, (52) holds true for t = s, since an empty product equals one, and for t ≥ s + 1 it is proven by an easy induction on t.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Consequently, T1f(s) = αs N � t=s+1 1 �t j=1 αj f(t).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since p, q ∈ (1, ∞), the elementary inequality of Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='7 is valid also when p is replaced by q.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It implies that for r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � r � k=1 αk �−q+1 ≥ min{1, q − 1} 2 N � k=r αk � k � j=1 αj �−q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (53) 21 Set A = 21/q min{1, q − 1}−1/q.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Since αk = w−1/(p−1) k and q/p = q − 1 = 1/(p − 1), it follows from (53) that for r = 1, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' , N, � r � k=1 wkαp k �1/p ≤ A \uf8eb \uf8ed N � k=r w−q/p k � k � j=1 αj �−q\uf8f6 \uf8f8 −1/q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' This is precisely the Muckenhoupt criterion from Corollary 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5, with U(k) = w1/p k αk and V (k) = w1/p k k � j=1 αj.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Thus, by Corollary 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='5, for any g : ΩN → R, N � k=1 wk �����αk N � ℓ=k g(ℓ) ����� p ≤ (CpA)p N � k=1 wk ����� � k � j=1 αj � g(k) ����� p , (54) with Cp = p1/pq1/q.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' By restricting attention to non-negative functions g in (54), we may alter (54) and replace �N ℓ=k by the shorter sum �N ℓ=k+1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Inequality (54) remains correct, for non- negative g, also after this modification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Denoting g(k) = f(k)/ �k j=1 αj, we conclude that for any non-negative function f : ΩN → R, N � k=1 wk �����αk N � ℓ=k+1 1 �ℓ j=1 αj f(ℓ) ����� p ≤ (CpA)p N � k=1 wk |f(k)|p .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' (55) Since the kernel of T1 is non-negative, its operator norm is attained at a non-negative function f : ΩN → R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Therefore (55) implies the required bound for the operator norm of T1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Proof of Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The kernel of the operator T is given in (38).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' It is a non-negative kernel, and therefore the operator norm of T is at most the operator norm of the operator whose kernel is the expression on the right-hand side of (38).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The latter operator equals T0 + T1 with T0 from Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='6 and T1 from Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='8.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' From these two propositions it follows that the operator norm of T is at most 21/pp1/pq1/q· max{1, (p − 1)−1/p} + 21/qp1/pq1/q · max{1, (q − 1)−1/q}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2 follows from Lemma 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1 and Proposition 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 22 Remarks.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' In this paper we have left open several natural questions, including the existence of linear extension operators for ˙W 1,p(T) for weighted trees T in the extreme cases p = 1, p = ∞, as well as the analog of our result for the inhomogeneous Sobolev space W 1,p(T) in place of ˙W 1,p(T).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The problem of existence of linear Sobolev extension operators for weighted trees arose in connection with an extension problem for W 1,p(R2).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' More precisely, given E ⊆ R2, let ˙W 1,p(E) denote the space of restrictions to E of functions in ˙W 1,p(R2), endowed with the natural seminorm.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Does there exist a linear extension operator from ˙W 1,p(E) to ˙W 1,p(R2)?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' The answer is affirmative for p ≥ 2;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' see A.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' Israel [3].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For 1 < p < 2, the answer is unknown.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' For a particular class of examples E, the problem reduces to the question answered by Theorem 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content='1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' References [1] Bj¨orn, A.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', Bj¨orn, J.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=', Gill, J.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/4NFST4oBgHgl3EQfZjjS/content/2301.13792v1.pdf'} +page_content=' T.' metadata={'source': 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