论文标题

$ \ {p,p+1,q-1,q \} $ - 方向的必要条件

A necessary and sufficient condition for the existence of $\{p,p+1,q-1,q\}$-orientations in simple graphs

论文作者

Hasanvand, Morteza

论文摘要

让$ g $是一个简单的图表,让$ p $和$ q $是$ v(g)$上的两个整数值函数,其中$ p <q $,其中每个$ v \ in v(g)$,$ q(v)\ ge \ ge \ frac {1} {1} {2} {2} {2} {2} d_g(v)$ p(v)$ p(v)$ p(v)$ p(v)在本说明中,我们表明$ g $具有一个方向,以至于每个顶点$ v $,$ d^+_ g(v)\ in \ {p(v),p(v)+1,q(v)-1,q(v)-1,q(v)\ q(v)\ y n且仅在为每个vertex $ v $ v $ p($ p d^)中提供方向, $ d^+_ g(v)$表示$ g $中的$ v $的超级度。从这个结果中,我们在两分的简单图中,在两分的简单图中,我们完善了结果。

Let $G$ be a simple graph and let $p$ and $q$ be two integer-valued functions on $V(G)$ with $p< q$ in which for each $v\in V(G)$, $q(v) \ge \frac{1}{2}d_G(v)$ and $p(v) \ge \frac{1}{2} q(v)-2$. In this note, we show that $G$ has an orientation such that for each vertex $v$, $d^+_G(v)\in\{p(v),p(v)+1,q(v)-1,q(v)\}$ if and only if it has an orientation such that for each vertex $v$, $p(v) \le d^+_G(v)\le q(v)$ where $d^+_G(v)$ denotes the out-degree of $v$ in $G$. From this result, we refine a result due to Addario-Berry, Dalal, and Reed (2008) in bipartite simple graphs on the existence of degree constrained factors.

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