Journal of Algorithms
Combinatorial optimization: algorithms and complexity
Combinatorial optimization: algorithms and complexity
An introduction to chromatic sums
CSC '89 Proceedings of the 17th conference on ACM Annual Computer Science Conference
On chromatic sums and distributed resource allocation
Information and Computation
Minimum color sum of bipartite graphs
Journal of Algorithms
Routing with Minimum Wire Length in the Dogleg-Free Manhattan Model is $\cal NP$-Complete
SIAM Journal on Computing
Edge-chromatic sum of trees and bounded cyclicity graphs
Information Processing Letters
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
The complexity of chromatic strength and chromatic edge strength
Computational Complexity
Complexity results for minimum sum edge coloring
Discrete Applied Mathematics
Minimum sum edge colorings of multicycles
Discrete Applied Mathematics
Minimum sum set coloring of trees and line graphs of trees
Discrete Applied Mathematics
On sum coloring and sum multi-coloring for restricted families of graphs
Theoretical Computer Science
Improved bounds for sum multicoloring and scheduling dependent jobs with minsum criteria
WAOA'04 Proceedings of the Second international conference on Approximation and Online Algorithms
On sum edge-coloring of regular, bipartite and split graphs
Discrete Applied Mathematics
Hi-index | 0.01 |
We consider the CHROMATIC SUM PROBLEM on bipartite graphs which appears to be much harder than the classical CHROMATIC NUMBER PROBLEM. We prove that the CHROMATIC SUM PROBLEM is NP-complete on planar bipartite graphs with 驴 驴 5, but polynomial on bipartite graphs with 驴 驴 3, for which we construct an O(n2)-time algorithm. Hence, we tighten the borderline of intractability for this problem on bipartite graphs with bounded degree, namely: the case 驴 = 3 is easy, 驴 = 5 is hard. Moreover, we construct a 27/26-approximation algorithm for this problem thus improving the best known approximation ratio of 10/9.