English

All fractional (g,f)-factors in graphs

Combinatorics 2014-12-15 v1

Abstract

Let GG be a graph, and g,f:V(G)Ng,f:V(G)\rightarrow N be two functions with g(x)f(x)g(x)\leq f(x) for each vertex xx in GG. We say that GG has all fractional (g,f)(g,f)-factors if GG includes a fractional rr-factor for every r:V(G)Nr:V(G)\rightarrow N such that g(x)r(x)f(x)g(x)\leq r(x)\leq f(x) for each vertex xx in GG. Let HH be a subgraph of GG. We say that GG admits all fractional (g,f)(g,f)-factors including HH if for every r:V(G)Nr:V(G)\rightarrow N with g(x)r(x)f(x)g(x)\leq r(x)\leq f(x) for each vertex xx in GG, GG includes a fractional rr-factor FhF_h with h(e)=1h(e)=1 for any eE(H)e\in E(H), then we say that GG admits all fractional (g,f)(g,f)-factors including HH, where h:E(G)[0,1]h:E(G)\rightarrow [0,1] is the indicator function of FhF_h. In this paper, we obtain a characterization for the existence of all fractional (g,f)(g,f)-factors including HH and pose a sufficient condition for a graph to have all fractional (g,f)(g,f)-factors including HH.

Keywords

Cite

@article{arxiv.1412.3882,
  title  = {All fractional (g,f)-factors in graphs},
  author = {Zhiren Sun and Sizhong Zhou},
  journal= {arXiv preprint arXiv:1412.3882},
  year   = {2014}
}

Comments

5 pages