Let and
be two independent planar Brownian motions, started at uniform points in the unit square and run for unit time. Let
be the intersection of their ranges, i.e., the set of points visited by both paths. Are all the connected components of
single points (almost surely on the event that
is nonempty) ?
It is known (see [1]) that the range of is intersection-equivalent in the unit square to a dyadic fractal percolation limit set
where squares of side-length are retained with probability
. We can deduce that
is
intersection-equivalent in the unit square to a fractal percolation limit set , where squares of side-length
are retained with probability
. It follows from [2] that
almost surely contains connected components that are larger than points; however, intersection equivalence is not strong enough to conclude that
also has this property.
[1] Peres, Yuval. "Intersection-equivalence of Brownian paths and certain branching processes." Communications in mathematical physics 177, no. 2 (1996): 417-434.
[2] Chayes, Jennifer T., Lincoln Chayes, and Richard Durrett. "Connectivity properties of Mandelbrot's percolation process." Probability theory and related fields 77, no. 3 (1988): 307-324.