Equation 12 · Part 1 · Einstein's Random Walk and the Mathematics of Genetic Drift
Symbol D
What this part means
the governed by a single constant.
Its job in the formula
D 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 D→Article meaning
Where the article explains it
Einstein’s equation described one physical system: particles buffeted by a fluid held at a fixed temperature, governed by a single constant D .
The passage around this formula
Einstein’s equation described one physical system: particles buffeted by a fluid held at a fixed temperature, governed by a single constant D . Within a decade, physicists working on an unrelated problem — how the energy of a rotating electric dipole settles under both random radiative kicks and a systematic damping force in a radiation field — found they needed the same mathematical object with one addition: a drift term standing alongside the diffusion term. Adriaan Fokker wrote down that generalization in 1914, and Max Planck rederived and extended it in 1917; the combined equation has carried both names since [ 3 ] . In one dimension it reads
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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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Sources cited in the surrounding passage
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