Black Scholes uses this system to model stock prices, and in the limit of continous variation this becomes a Weiner process.
RDFs describe this process in two-state systems common in biology. Watson's triple integrals appear in Polya's treatment of the level crossing phenomenon of this process in higher dimensions.  The Skorokhod embedding thoerem relates this process to its continuous limit. The Hurst exponent describes the self-correlation in this process. Levy names a type of this process where lengths are distributed according to an inverse power law. The excluded volume condition is added to use this process to model polymer physics. In one dimension, the variance is proportional to the square root of n, while in one and two dimensions the return probability is one.  Black Scholes uses this system to model stock prices, and in the limit of continous variation this becomes a Weiner process. Typically modeled as a markov process, FTP, name this process similar to Brownian motion in which an actor takes steps.
RDFs describe this process in two-state systems common in biology.
{Random Walk}