RAG Query Optimizer

Optimize this query for RAG (Retrieval-Augmented Generation) retrieval:
Original query: "[query]"
Documentation/knowledge base topic: [topic]

Generate: (1) 5 query reformulations using different vocabulary (semantic expansion). (2) HyDE version (hypothetical document embedding). (3) Decomposed sub-queries for complex questions. (4) Metadata filter suggestions. (5) Re-ranking scoring criteria. (6) The composite query strategy that maximizes recall precision. Explain the retrieval theory behind each technique.