English

Elusive groups from non-split extensions

Group Theory 2026-03-19 v3

Abstract

A finite transitive permutation group is elusive if it contains no derangements of prime order. These groups are closely related to a longstanding open problem in algebraic graph theory known as the Polycirculant Conjecture, which asserts that no elusive group is 22-closed. Existing constructions of elusive groups mostly arise from split extensions. In this paper, we initiate the construction of elusive groups via non-split extensions. As a demonstration, we construct elusive groups of new degrees, namely p3k4(p+1)/2p^{3k-4}(p+1)/2 for each Mersenne prime p7p\geq7 and integer k2k\geq2. We also construct the first examples of elusive groups with odd degree, namely 3k+1523^{k+1}\cdot5^2, and twice odd degree, namely 23k+1522\cdot3^{k + 1}\cdot5^2 for each k1k\geq1. We conclude by proposing further problems to advance this new direction of research.

Keywords

Cite

@article{arxiv.2508.12652,
  title  = {Elusive groups from non-split extensions},
  author = {Jiyong Chen and Melissa Lee and Dorde Mitrovic and E. A. O'Brien and Binzhou Xia},
  journal= {arXiv preprint arXiv:2508.12652},
  year   = {2026}
}