Equation 13 · Part 1 · Ten Failure Modes That Define Production RAG
Symbol k_eff
What this part means
ff is part of the quantity the equation computes from the expression on the right.
Its job in the formula
ff is part of the quantity the equation computes from the expression on the right.
Full expression→Symbol k_eff→Article meaning
The passage around this formula
Real corpora are full of near-duplicates: a press release syndicated across a dozen outlets, a policy document copied into three different wikis, boilerplate repeated at the top of every ticket in 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…
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
See this notation across published equations →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.