English

Decompositions of graphs of nonnegative characteristic with some forbidden subgraphs

Combinatorics 2022-04-19 v1

Abstract

A {\em (d,h)(d,h)-decomposition} of a graph GG is an order pair (D,H)(D,H) such that HH is a subgraph of GG where HH has the maximum degree at most hh and DD is an acyclic orientation of GE(H)G-E(H) of maximum out-degree at most dd. A graph GG is {\em (d,h)(d, h)-decomposable} if GG has a (d,h)(d,h)-decomposition. Let GG be a graph embeddable in a surface of nonnegative characteristic. In this paper, we prove the following results. (1) If GG has no chord 55-cycles or no chord 66-cycles or no chord 77-cycles and no adjacent 44-cycles, then GG is (3,1)(3,1)-decomposable, which generalizes the results of Chen, Zhu and Wang [Comput. Math. Appl, 56 (2008) 2073--2078] and the results of Zhang [Comment. Math. Univ. Carolin, 54(3) (2013) 339--344]. (2) If GG has no ii-cycles nor jj-cycles for any subset {i,j}{3,4,6}\{i,j\}\subseteq \{3,4,6\} is (2,1)(2,1)-decomposable, which generalizes the results of Dong and Xu [Discrete Math. Alg. and Appl., 1(2) (2009), 291--297].

Keywords

Cite

@article{arxiv.2204.08161,
  title  = {Decompositions of graphs of nonnegative characteristic with some forbidden subgraphs},
  author = {Lin Niu and Xiangwen Li},
  journal= {arXiv preprint arXiv:2204.08161},
  year   = {2022}
}

Comments

15 pages,7 figures