A Note on Chromatic Sum
Meysam Alishahi, Ali Taherkhani · arXiv (Cornell University) · 2008
The chromatic sum $Σ(G)$ of a graph $G$ is the smallest sum of colors among of proper coloring with the natural number. In this paper, we introduce a necessary condition for the existence of graph homomorphisms. Also, we present $Σ(G)