论文标题
$ \ {p,q \} $ - 方向的存在在边缘连接图中
The existence of $\{p,q\}$-orientations in edge-connected graphs
论文作者
论文摘要
1976年,弗兰克(Frank)和gy {á} rf {á} s在任意图$ g $中存在方向的必要条件,使每个顶点$ v $,$ d^+_ g(v)的每个顶点$ d^+_ g(v)的$ p(v)$ p(v) $ v(g)$上的整数值函数,带有$ p \ le q $。在本文中,我们给出了足够的边缘连接性条件,以在$ g $中存在一个方向,以使每个顶点$ v $,$ d^+_ g(v)\ in \ {p(v),q(v)\} $,规定每个vertex $ v $ v $,$ p(v) q(v)$,$ | q(v)-p(v)| \ le k $,并且有$ t(v)\ in \ {p(v),q(v)\} $,其中$ | e(g)| = \ sum_ {v \ in v(g)} t(v)t(v)$。该结果是由于Thomassen(2012)在高度边缘连接图中存在模量方向而引起的定理的概括。
In 1976 Frank and Gy{á}rf{á}s gave a necessary and sufficient condition for the existence of an orientation in an arbitrary graph $G$ such that for each vertex $v$, the out-degree $d^+_G(v)$ of it satisfies $p(v)\le d^+_G(v)\le q(v)$, where $p$ and $q$ are two integer-valued functions on $V(G)$ with $p\le q$. In this paper, we give a sufficient edge-connectivity condition for the existence of an orientation in $G$ such that for each vertex $v$, $d^+_G(v)\in \{p(v),q(v)\}$, provided that for each vertex $v$, $p(v)\le \frac{1}{2}d_G(v) \le q(v)$, $|q(v)-p(v)|\le k$, and there is $t(v)\in \{p(v),q(v)\}$ in which $|E(G)|=\sum_{v\in V(G)}t(v)$. This result is a generalization of a theorem due to Thomassen (2012) on the existence of modulo orientations in highly edge-connected graphs.