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Equation 10 · Part 3 · The Arrow of Time and the Engine of Evolution

subscript

PF(W)P_{\mathrm F}(W)
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

Gavin Crooks sharpened this two years later into a statement about entire probability distributions rather than a single average. If PF(W)P_{\mathrm F}(W) is the distribution of work values measured over many repetitions of a forward protocol, and PR(W)P_{\mathrm R}(W) is the distribution measured over the time-reversed protocol run from its own correctly defined reverse-equilibrium starting ensemble, the two distributions are related by

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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 article section

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