English

Laminations of a graph on a pair of pants

Combinatorics 2020-12-07 v3 Geometric Topology

Abstract

A lamination of a graph embedded on a surface is a collection of pairwise disjoint non-contractible simple closed curves drawn on the graph. In the case when the surface is a sphere with three punctures (a.k.a. a pair of pants), we first identify the lamination space of a graph embedded on that surface as a lattice polytope, then we characterize the polytopes that arise as the lamination space of some graph on a pair of pants. This characterizes the image of a purely topological version of the spectral map for the vector bundle Laplacian for a flat connection on a pair of pants. The proof uses a graph exploration technique akin to the peeling of planar maps.

Keywords

Cite

@article{arxiv.1804.01968,
  title  = {Laminations of a graph on a pair of pants},
  author = {Sanjay Ramassamy},
  journal= {arXiv preprint arXiv:1804.01968},
  year   = {2020}
}

Comments

17 pages, 8 figures. Final version to appear in the Bulletin of the London Mathematical Society