English

Graphs that contain multiply transitive matchings

Combinatorics 2020-08-17 v3

Abstract

Let Γ\Gamma be a finite, undirected, connected, simple graph. We say that a matching M\mathcal{M} is a \textit{permutable mm-matching} if M\mathcal{M} contains mm edges and the subgroup of Aut(Γ)\text{Aut}(\Gamma) that fixes the matching M\mathcal{M} setwise allows the edges of M\mathcal{M} to be permuted in any fashion. A matching M\mathcal{M} is \textit{2-transitive} if the setwise stabilizer of M\mathcal{M} in Aut(Γ)\text{Aut}(\Gamma) can map any ordered pair of distinct edges of M\mathcal{M} to any other ordered pair of distinct edges of M\mathcal{M}. We provide constructions of graphs with a permutable matching; we show that, if Γ\Gamma is an arc-transitive graph that contains a permutable mm-matching for m4m \ge 4, then the degree of Γ\Gamma is at least mm; and, when mm is sufficiently large, we characterize the locally primitive, arc-transitive graphs of degree mm that contain a permutable mm-matching. Finally, we classify the graphs that have a 22-transitive perfect matching and also classify graphs that have a permutable perfect matching.

Keywords

Cite

@article{arxiv.1706.08964,
  title  = {Graphs that contain multiply transitive matchings},
  author = {Alex Schaefer and Eric Swartz},
  journal= {arXiv preprint arXiv:1706.08964},
  year   = {2020}
}

Comments

to appear in European Journal of Combinatorics

R2 v1 2026-06-22T20:31:22.455Z