Self-avoiding random loops

Abstract

A random loop, or polygon, is a simple random walk whose trajectory is a simple Jordan curve. The study of random loops is extended in two ways. First, the probability P/sub n/(x,y) that a random n-step loop contains a point (x,y) in the interior of the loop is studied, and (1/2, 1/2) is shown to be (1/2)-(1/n). It is plausible that P/sub n/(x,y) tends toward 1/2 for all (x,y), but this is not proved even for (x,y)=(3/2,1/2) A way is offered to simulate random n-step self-avoiding loops. Numerical evidence obtained with this simulation procedure suggests that the probability P/sub n/(3/2,1/2) approximately=(1/2)-(c/n), for some fixed c. >