文摘
Let \(G\) be a graph and \(f:V(G)\rightarrow \{1,2,3,4,\ldots \}\) be a function. We denote by \(odd(G)\) the number of odd components of \(G\). We prove that if \(odd(G-X)\le \sum _{x\in X}f(x)\) for all \( X\subset V(G)\), then \(G\) has a \((1,f)\)-factor \(F\) such that, for every vertex \(v\) of \(G\), if \(f(v)\) is even, then \(\deg _F(v)\in \{1,3,\ldots ,f(v)-1,f(v)\}\), and otherwise \(\deg _F(v)\in \{1,3, \ldots , f(v)\}\). This theorem is a generalization of both the \((1,f)\)-odd factor theorem and a recent result on \(\{1,3, \ldots , 2n-1,2n\}\)-factors by Lu and Wang. We actually prove a result stronger than the above theorem. Keywords Factor of graph \(( 1, f)\)-Odd factor Odd components