On traces of randomly rolling polytopes
Combinatorics
2026-08-06 v1
Abstract
Let be a three-dimensional convex polytope resting with one of its faces on the plane. At each step, is allowed to roll over a randomly selected edge of the face currently lying on the plane, until the adjacent face comes to rest on the plane. The trace of is the set of all points of the plane that can be reached by a vertex of , starting from a fixed initial position and performing a finite sequence of rolls. We prove that if the trace of has a convergent subsequence, then, with probability one, the set of points reached by the vertices of a randomly rolling copy of is everywhere dense in the plane. This settles a conjecture of Hegyv\'ari.
Keywords
Cite
@article{arxiv.2608.05721,
title = {On traces of randomly rolling polytopes},
author = {Kenneth Moore and János Pach},
journal= {arXiv preprint arXiv:2608.05721},
year = {2026}
}
Comments
15 pages, 2 figures