On the complexity of H-coloring
Journal of Combinatorial Theory Series B
A simple proof of the multiplicativity of directed cycles of prime power length
Discrete Applied Mathematics
The Existence of Homomorphisms to Oriented Cycles
SIAM Journal on Discrete Mathematics
Approximation results for the optimum cost chromatic partition problem
Journal of Algorithms
Classification of Homomorphisms to Oriented Cycles and of k-Partite Satisfiability
SIAM Journal on Discrete Mathematics
Minimizing Average Completion of Dedicated Tasks and Interval Graphs
APPROX '01/RANDOM '01 Proceedings of the 4th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems and 5th International Workshop on Randomization and Approximation Techniques in Computer Science: Approximation, Randomization and Combinatorial Optimization
Communication: Minimum cost homomorphisms to semicomplete multipartite digraphs
Discrete Applied Mathematics
Digraphs: Theory, Algorithms and Applications
Digraphs: Theory, Algorithms and Applications
Communication: Level of repair analysis and minimum cost homomorphisms of graphs
Discrete Applied Mathematics
Communication: Minimum cost and list homomorphisms to semicomplete digraphs
Discrete Applied Mathematics
Minimum cost homomorphisms to reflexive digraphs
LATIN'08 Proceedings of the 8th Latin American conference on Theoretical informatics
Minimum cost homomorphisms to oriented cycles with some loops
CATS '09 Proceedings of the Fifteenth Australasian Symposium on Computing: The Australasian Theory - Volume 94
Extensions of the minimum cost homomorphism problem
COCOON'10 Proceedings of the 16th annual international conference on Computing and combinatorics
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For digraphs Dand H, a mapping f: V(D) 驴V(H) is a homomorphism of Dto Hif uv驴 A(D) implies f(u)f(v) 驴 A(H). If, moreover, each vertex u驴 V(D) is associated with costs ci(u), i驴 V(H), then the cost of the homomorphism fis 驴 u驴 V(D)cf(u)(u). For each fixed digraph H, we have the minimum cost homomorphism problem forH(abbreviated MinHOM(H)). In this discrete optimization problem, we are to decide, for an input graph Dwith costs ci(u), u驴 V(D), i驴 V(H), whether there exists a homomorphism of Dto Hand, if one exists, to find one of minimum cost. We obtain a dichotomy classification for the time complexity of MinHOM(H) when His an oriented cycle. We conjecture a dichotomy classification for all digraphs with possible loops.