Halfway to induced saturation for even cycles
Abstract
For graphs and , we say that is -free if no induced subgraph of is isomorphic to , and that is -induced-saturated if is -free but removing or adding any edge in creates an induced copy of . A full characterization of graphs for which -induced-saturated graphs exist remains elusive. Even the case where is a path -- now settled by the collective results of Martin and Smith, Bonamy et al., and Dvo\'{r}\v{a}k -- was already quite challenging. What if is a cycle? The complete answer for odd cycles was given by Behren et al., leaving the case of even cycles (except for the -cycle) wide open. Our main result is the first step toward closing this gap: We prove that for every even cycle , there is a graph with at least one edge such that is -free but removing any edge from creates an induced copy of (in fact, we construct -induced-saturated graphs for every even cycle on at most 10 vertices).
Keywords
Cite
@article{arxiv.2505.24100,
title = {Halfway to induced saturation for even cycles},
author = {Xinyue Fan and Sahab Hajebi and Sepehr Hajebi and Sophie Spirkl},
journal= {arXiv preprint arXiv:2505.24100},
year = {2025}
}