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Equation 11 · Part 2 · The Arrow of Time and the Engine of Evolution

Symbol W

PR(W)P_{\mathrm R}(W)
WW

What this part means

W 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

W is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

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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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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