Equation 13 · Part 2 · Ten Failure Modes That Define Production RAG
Symbol k
What this part means
the number of retrieved slots.
Its job in the formula
k is part of the quantity the equation computes from the expression on the right.
Full expression→Symbol k→Article meaning
Where the article explains it
If d of the k retrieved slots are occupied by near-duplicates of an already-retrieved passage, the effective evidence budget is not k but .
The passage around this formula
…a queue. A ranking function that scores by similarity to the query has no reason to penalise duplication, so a query that matches one instance of a widely republished passage tends to match all of them, and a naive top- k selection can fill a majority of its slots with restatements of a single fact rather than covering the breadth of what is actually in the corpus. If d of the k retrieved slots are occupied by near-duplicates of an already-retrieved passage, the effective evidence budget is not k but [displayed…
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
These citations provide research context; check each source for the exact claim it supports.