← All parts of this equation

Equation 13 · Part 3 · Retrieval Is an Evidence System, Not a Memory

subscript

Zk(x)\mathcal{Z}_k(x)
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

Suppose retrieval succeeds. The relevant passage is in Zk(x)\mathcal{Z}_k(x) , correctly chunked, in the prompt. The system may still fail, for a reason that has nothing to do with retrieval quality.

Read this part in the article →

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 →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.