English

Bounds on saddle connections for flat spheres

Geometric Topology 2026-05-07 v2 Differential Geometry

Abstract

We consider a flat metric with conical singularities on the sphere. Under the assumption that no partial sum of angle defects is equal to 2π2\pi, we draw on the geometry of immersed disks to obtain an explicit upper bound on the number of saddle connections with at most kk self-intersections. Additionally, we establish an upper bound on their lengths for a surface with a normalized area. Finally, we apply these bounds to the counting of singular trajectories in irrational polygonal billiards.

Keywords

Cite

@article{arxiv.2308.08940,
  title  = {Bounds on saddle connections for flat spheres},
  author = {Kai Fu and Guillaume Tahar},
  journal= {arXiv preprint arXiv:2308.08940},
  year   = {2026}
}

Comments

27 pages, 17 figures, to appear in Journal of Topology

R2 v1 2026-06-28T11:57:53.737Z