English

Flip-graphs of non-orientable filling surfaces

Geometric Topology 2025-05-08 v1 Combinatorics

Abstract

Consider a surface Σ\Sigma with punctures that serve as marked points and at least one marked point on each boundary component. We build a filling surface Σn\Sigma_n by singling out one of the boundary components and denoting by nn the number of marked points it contains. We consider the triangulations of Σn\Sigma_n whose vertices are the marked points and the associated flip-graph F(Σn)\mathcal{F}(\Sigma_n). Quotienting F(Σn)\mathcal{F}(\Sigma_n) by the homeomorphisms of Σ\Sigma that fix the privileged boundary component results in a finite graph MF(Σn)\mathcal{MF}(\Sigma_n). Bounds on the diameter of MF(Σn)\mathcal{MF}(\Sigma_n) are available when Σ\Sigma is orientable and we provide corresponding bounds when Σ\Sigma is non-orientable. We show that the diameter of this graph grows at least like 5n/25n/2 and at most like 4n4n as nn goes to infinity. If Σ\Sigma is an unpunctured M\"obius strip, MF(Σn)\mathcal{MF}(\Sigma_n) coincides with F(Σn)\mathcal{F}(\Sigma_n) and we prove that the diameter of this graph grows exactly like 5n/25n/2 as nn goes to infinity.

Keywords

Cite

@article{arxiv.2505.04074,
  title  = {Flip-graphs of non-orientable filling surfaces},
  author = {Pallavi Panda and Hugo Parlier and Lionel Pournin},
  journal= {arXiv preprint arXiv:2505.04074},
  year   = {2025}
}

Comments

37 pages, 17 figures