A generalized Tur\'an problem in random graphs
Abstract
We study the following generalization of the Tur\'an problem in sparse random graphs. Given graphs and , let be the random variable that counts the largest number of copies of in a subgraph of that does not contain . We study the threshold phenomena arising in the evolution of the typical value of this random variable, for every and an arbitrary -balanced . Our results in the case when are a natural generalization of the Erd\H{o}s--Stone theorem for , which was proved several years ago by Conlon and Gowers and by Schacht; the case has been recently resolved by Alon, Kostochka, and Shikhelman. More interestingly, the case when exhibits a more complex and subtle behavior. Namely, the location(s) of the (possibly multiple) threshold(s) are determined by densities of various coverings of with copies of and the typical value(s) of are given by solutions to deterministic hypergraph Tur\'an-type problems that we are unable to solve in full generality.
Keywords
Cite
@article{arxiv.1806.06609,
title = {A generalized Tur\'an problem in random graphs},
author = {Wojciech Samotij and Clara Shikhelman},
journal= {arXiv preprint arXiv:1806.06609},
year = {2019}
}