English

Generalized Tur\'an problem for directed cycles

Combinatorics 2025-05-29 v1

Abstract

For integers k,3k, \ell \geq 3, let ex(n,Ck,C)\mathrm{ex}(n, \overrightarrow{C_k}, \overrightarrow{C_\ell}) denote the maximum number of directed cycles of length kk in any oriented graph on nn vertices which does not contain a directed cycle of length \ell. We establish the order of magnitude of ex(n,Ck,C)\mathrm{ex}(n, \overrightarrow{C_k}, \overrightarrow{C_\ell}) for every kk and \ell and determine its value up to a lower error term when kk \nmid \ell and \ell is large enough. Additionally, we calculate the value of ex(n,Ck,C)\mathrm{ex}(n, \overrightarrow{C_k}, \overrightarrow{C_\ell}) for some other specific pairs (k,)(k, \ell) showing that a diverse class of extremal constructions can appear for small values of \ell.

Keywords

Cite

@article{arxiv.2505.22189,
  title  = {Generalized Tur\'an problem for directed cycles},
  author = {Andrzej Grzesik and Justyna Jaworska and Bartłomiej Kielak and Piotr Kuc and Tomasz Ślusarczyk},
  journal= {arXiv preprint arXiv:2505.22189},
  year   = {2025}
}
R2 v1 2026-07-01T02:45:55.859Z