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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2016 Volume 450, Pages 5–13 (Mi znsl6333)

On the connection between the chromatic number of a graph and the number of cycles, covering a vertex or an edge

S. L. Berlov, K. I. Tyschuk

Physical and Mathematical Lyceum 239, St. Petersburg, Russia

Abstract: We prove several tight bounds on the chromatic number of a graph in terms of the minimal number of simple cycles, covering a vertex or an edge of this graph. Namely, we prove that $\chi(G)\leq k$ in the following two cases: any edge of $G$ is covered by less than $[e(k-1)!-1]$ simple cycles or any vertex of $G$ is covered by less than $[\frac{ek!}2-\frac{k+1}2]$ simple cycles. Tight bounds on the number of simple cycles covering an edge or a vertex of a $k$-critical graph are also proved.

Key words and phrases: proper coloring, chromatic number.

UDC: 519.174.7

Received: 11.10.2016


 English version:
Journal of Mathematical Sciences (New York), 2018, 232:1, 1–5

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© Steklov Math. Inst. of RAS, 2024