Pentagons in triangle-free graphs
arXiv:1712.08869 · doi:10.1016/j.ejc.2018.07.008
Abstract
For all , we show that the only triangle-free graphs on vertices maximizing the number -cycles are balanced blow-ups of a 5-cycle. This completely resolves a conjecture by Erdős, and extends results by Grzesik and Hatami, Hladký, Král', Norin and Razborov, where they independently showed this same result for large and for all divisible by .
6 pages