Equation 14 · Part 2 · Einstein's Random Walk and the Mathematics of Genetic Drift
Symbol x
What this part means
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x is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
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The passage around this formula
where the first right-hand term carries the probability density along a deterministic drift and the second spreads it by diffusion at rate D(x,t) [ 3 ] . Andrei Kolmogorov arrived at the identical equation independently in 1931, from pure probability theory, as the forward equation governing how the probability distribution of any continuous-time Markov process evolves [ 3 ] . Kolmogorov’s work also produced a companion equation, run backward in time from a fixed outcome rather than forward from a fixed start, that turns out to be the more convenient tool for asking what a process is heading toward rather than where it began — a distinction that mattered when the same mathematics…
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Sources cited in the surrounding passage
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