English

On vertex-transitive graphs with a unique hamiltonian cycle

Combinatorics 2023-04-20 v2

Abstract

A graph is said to be uniquely hamiltonian if it has a unique hamiltonian cycle. For a natural extension of this concept to infinite graphs, we find all uniquely hamiltonian vertex-transitive graphs with finitely many ends, and also discuss some examples with infinitely many ends. In particular, we show each nonabelian free group FnF_n has a Cayley graph of degree 2n+22n + 2 that has a unique hamiltonian circle. (A weaker statement had been conjectured by A. Georgakopoulos.) Furthermore, we prove that these Cayley graphs of FnF_n are outerplanar.

Keywords

Cite

@article{arxiv.2303.11124,
  title  = {On vertex-transitive graphs with a unique hamiltonian cycle},
  author = {Babak Miraftab and Dave Witte Morris},
  journal= {arXiv preprint arXiv:2303.11124},
  year   = {2023}
}
R2 v1 2026-06-28T09:24:12.506Z