Equation 5 · Part 1 · Naive, Graph, and Agentic: A Systems Comparison of RAG Architectures
Symbol k
What this part means
k is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Its job in the formula
k is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol k→Article meaning
The passage around this formula
Start with the architecture that gives the pattern its name. A query is encoded, a retriever returns its top- k passages against a fixed index, and a generator conditions on those passages to produce one answer. No step revisits an earlier one. Lewis and colleagues’ original formulation makes the mechanism explicit: writing x for the query, y for the output, and z for a retrieved passage drawn from a top- k set , the model marginalises over that set,
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 article section
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