RAG
Dense retrieval
Dense retrieval ranks items using learned vector representations.
How it works
An encoder maps queries and documents into a shared space. Semantic neighbors can match even when they share few exact words.
A concrete example
Illustrative: “reset password” retrieves “account credential recovery” at similarity 0.84.
Do not confuse it with Sparse retrieval
dense retrieval uses learned vectors; sparse retrieval relies on term-weighted dimensions.