On the size of special class 1 graphs and $(P_3;k)$-co-critical graphs

Gang Chen, Zhengke Miao, Zi-Xia Song +1

A well-known theorem of Vizing states that if $G$ is a simple graph with maximum degree $\Delta$, then the chromatic index ${\chi }^{\prime }(G)$ of $G$ is $\Delta$ or $\Delta +1$. A graph $G$ is class 1 if $χ'(…