English

Density of convex billiards with rational caustics

Dynamical Systems 2018-11-14 v2

Abstract

We show that in the space of all convex billiard boundaries, the set of boundaries with rational caustics is dense. More precisely, the set of billiard boundaries with caustics of rotation number 1/q1/q is polynomial sense in the smooth case, and exponentially dense in the analytic case.

Keywords

Cite

@article{arxiv.1706.07968,
  title  = {Density of convex billiards with rational caustics},
  author = {Vadim Kaloshin and Ke Zhang},
  journal= {arXiv preprint arXiv:1706.07968},
  year   = {2018}
}

Comments

22 pages, corrections and clarifications added from last version

R2 v1 2026-06-22T20:28:33.787Z