论文标题
某些面向注射性着色的障碍物
Obstructions to some injective oriented colourings
论文作者
论文摘要
对定向图$ h $的同型图$ g $同态的局部注射率的几个可能定义都导致了面向注入的着色问题。对于每种在多项式时间都可以解决的情况，我们确定了面向图形的集合$ \ MATHCAL {f} $，以便在\ Mathcal {f}中没有$ f \ in \ nathcal {f} $ fog的$ flos $ hom $ horm $ hom gen $ hom gen $ hom gen $ hom的$ f \ in the $ f \ n of给定数量时，$ hom是$ horm的$。
Each of several possible definitions of local injectivity for a homomorphism of an oriented graph $G$ to an oriented graph $H$ leads to an injective oriented colouring problem. For each case in which such a problem is solvable in polynomial time, we identify a set $\mathcal{F}$ of oriented graphs such that an oriented graph $G$ has an injective oriented colouring with the given number of colours if and only if there is no $F \in \mathcal{F}$ for which there is a locally-injective homomorphism of $F$ to $G$.
