A counterexample to a conjecture about triangle-free induced subgraphs of graphs with large chromatic number

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چکیده

We prove that for every $n$, there is a graph $G$ with $\chi(G) \geq n$ and $\omega(G) \leq 3$ such induced subgraph $H$ of $\omega(H) 2$ satisfies $\chi(H) 4$. This disproves well-known conjecture. Our construction digraph bounded clique number, large dichromatic no directed cycles odd length at least 5.

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ژورنال

عنوان ژورنال: Journal of Combinatorial Theory, Series B

سال: 2023

ISSN: ['0095-8956', '1096-0902']

DOI: https://doi.org/10.1016/j.jctb.2022.09.001