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Equation 20 · Part 2 · Naive, Graph, and Agentic: A Systems Comparison of RAG Architectures

subscript

CindexC_{\text{index}}
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

When Q is small — a corpus queried rarely, or one still being explored — CindexC_{\text{index}} dominates and the naive or hybrid architectures are cheaper by a wide margin, because they pay nothing until a query arrives. When Q is large against a stable corpus, the fixed term is driven down toward zero and the comparison turns on cmarginalc_{\text{marginal}} against the per-query cost of the alternatives. The direction of that comparison depends on the question being asked, not only on volume: Edge and colleagues report that GraphRAG produces substantially more comprehensive and diverse answers than a conventional RAG baseline specifically on query-focused summarisation over large corpora, the kind of…

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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.

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Sources cited in the surrounding passage

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