Equation 14 · Part 4 · Naive, Graph, and Agentic: A Systems Comparison of RAG Architectures
Symbol k
What this part means
the smoothing constant.
Its job in the formula
k occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.
Full expression→Symbol k→Article meaning
Where the article explains it
Reciprocal rank fusion, which Cormack and colleagues introduced and showed outperforming both individual rankers and a Condorcet-style combination, ignores raw scores entirely and combines rank positions across retrievers R with a smoothing constant k , .
The passage around this formula
…Cormack and colleagues introduced and showed outperforming both individual rankers and a Condorcet-style combination, ignores raw scores entirely and combines rank positions across retrievers R with a smoothing constant k , . sidestepping the problem that a BM25 score and a cosine similarity are not directly comparable quantities [ 3 ] . A reranking stage — typically a cross-encoder scoring each retrieved candidate jointly with the query — can then sit downstream of the fused list and reorder it…
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
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Sources cited in the surrounding passage
- [2] Dense Passage Retrieval for Open-Domain Question Answering ↗
- [3] Reciprocal Rank Fusion Outperforms Condorcet and Individual Rank Learning Methods ↗
These citations provide research context; check each source for the exact claim it supports.