English

Quasirandom forcing orientations of cycles

Combinatorics 2023-07-14 v3

Abstract

An oriented graph HH is quasirandom-forcing if the limit (homomorphism) density of HH in a sequence of tournaments is 2H2^{-\|H\|} if and only if the sequence is quasirandom. We study generalizations of the following result: the cyclic orientation of a cycle of length \ell is quasirandom-forcing if and only if 2\ell\equiv 2 mod 44. We show that no orientation of an odd cycle is quasirandom-forcing. In the case of even cycles, we find sufficient conditions on an orientation to be quasirandom-forcing, which we complement by identifying necessary conditions. Using our general results and spectral techniques used to obtain them, we classify which orientations of cycles of length up to 1010 are quasirandom-forcing.

Keywords

Cite

@article{arxiv.2212.09343,
  title  = {Quasirandom forcing orientations of cycles},
  author = {Andrzej Grzesik and Daniel Il'kovič and Bartłomiej Kielak and Daniel Král'},
  journal= {arXiv preprint arXiv:2212.09343},
  year   = {2023}
}
R2 v1 2026-06-28T07:41:48.665Z