query.md

### Query Encoding

Let's start by exploring SPLADE's query encoder. The query encoder is a `Q→Q` (query rewriting, query-to-query) transformer, and can be used in pipelines accordingly.
It maps a query string into a sparse `dict`-formatted query vector, with the tokens as the keys and the weights as values.

<div class="pipeline">
  <div class="df" title="Query Frame">Q</div>
  <div class="transformer attn" title="SPLADE Query Transformer">SPLADE</div>
  <div class="df" title="Query Frame">Q</div>
</div>