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JOURNALS // Sibirskie Èlektronnye Matematicheskie Izvestiya [Siberian Electronic Mathematical Reports] // Archive

Sib. Èlektron. Mat. Izv., 2007 Volume 4, Pages 435–439 (Mi semr165)

This article is cited in 2 papers

Research papers

Minimax degrees of quasiplane graphs without $4$-faces

O. V. Borodina, A. O. Ivanovab, A. V. Kostochkaa, N. N. Sheikhc

a Sobolev Institute of Mathematics, Novosibirsk, Russia
b Yakutsk State University
c Department of Mathematics, University of Illinois Department of Mathematics, Urbana, USA

Abstract: The $M$-degree of an edge $xy$ in a graph is the maximum of the degrees of $x$ and $y$. The minimax degree of a graph $G$ is the minimum over $M$-degrees of its edges. In order to get upper bounds on the game chromatic number, W. He et al showed that every planar graph $G$ without leaves and $4$-cycles has minimax degree at most $8$. This was improved by Borodin et al to the best possible bound $7$. Answering a question by D. West, we show that every plane graph $G$ without leaves and $4$-faces has minimax degree at most $15$. The bound is sharp. Similar results are obtained for graphs embeddable on the projective plane, torus and Klein bottle.

UDC: 519.172.2

MSC: 05С15

Received October 3, 2007, published October 16, 2007

Language: English



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