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Equation 8 · Part 3 · What Actually Happens Between a Query and an Answer in RAG

Symbol R

RRF(d)=∑r∈R1k+r(d)\mathrm{RRF}(d) = \sum_{r \in R} \frac{1}{k + r(d)}
RR

What this part means

R appears in the bound of this sum. The bound states where the repeated operation starts, ends, or which values it includes.

Its job in the formula

R appears in the bound of this sum. The bound states where the repeated operation starts, ends, or which values it includes.

The passage around this formula

Reciprocal rank fusion avoids the currency problem by discarding scores altogether and combining rank positions instead. For a document d and a set of ranked result lists R , with r(d) the rank of d in a given list and a smoothing constant k : RRF(d)=∑r∈R1k+r(d)\mathrm{RRF}(d) = \sum_{r \in R} \frac{1}{k + r(d)}. Cormack, Clarke, and Buettcher introduced the method and reported that it consistently outperformed both the individual ranked lists and a Condorcet-style fusion baseline, with the specific virtue that it…

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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

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