This paper considers problems of the following type: given an edgeweighted k-colored input graph with maximum color class size c, find a minimum or maximum c-way cut such that eac...
We study complexity and approximation of min weighted node coloring in planar, bipartite and split graphs. We show that this problem is NP-complete in planar graphs, even if they a...
We present a polynomial-time approximation algorithm for legally coloring as many edges of a given simple graph as possible using two colors. It achieves an approximation ratio of ...
We consider the following vertex coloring problem. We are given an undirected graph G = (V, E), where each vertex v is associated with a penalty rejection cost rv. We need to choos...
The problem of computing the chromatic number of a P5-free graph (a graph which contains no path on 5 vertices as an induced subgraph) is known to be NP-hard. However, we show tha...