← All parts of this equation

Equation 15 · Part 1 · Einstein's Random Walk and the Mathematics of Genetic Drift

Symbol D

D(x,t)D(x,t)
DD

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.

Where the article explains it

The Random Walk Gets a General Law 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

where the first right-hand term carries the probability density along a deterministic drift μ(x,t)\mu(x,t) 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…

Read this part in the article →

Learn the underlying idea

A function assigns an output to each allowed input. The expression f(x) means “apply f to x”.

Open the illustrated functions: inputs become outputs guide →

See this notation across published equations →

Sources cited in the surrounding passage

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