We prove that the distance between two reflected Brownian motions, driven by
the same white noise, outside a sphere in a 3-dimensional flat torus does not
converge to 0, a.s., if the radius of the sphere is sufficiently small,
relative to the size of the torus.Comment: Published in at http://dx.doi.org/10.1214/12-AOP831 the Annals of
Probability (http://www.imstat.org/aop/) by the Institute of Mathematical
Statistics (http://www.imstat.org