Chromatic Number and Dichromatic Polynomial of Digraphs

Saeed Akbari, Amir Hossein Ghodrati, Afrouz Jabalameli +1

Let $G$ be a graph of order $n$. It is well-known that $\alpha (G)\ge {\sum }_{i=1}^n\frac{1}{1+d_i}$, where $\alpha (G)$ is the independence number of $G$ and $d_1,\dots ,d_n$ is the degree se…