Parameterized algorithms for min-max multiway cut and list digraph homomorphism
•We design FPT-algorithms for the following two parameterized problems:•List Digraph Homomorphism, which is a “list” version of the classical Digraph Homomorphism problem.•Min-Max Multiway Cut, which is a variant of Multiway Cut.•We introduce a general problem, List Allocation, and we present parame...
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| Vydáno v: | Journal of computer and system sciences Ročník 86; s. 191 - 206 |
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| Hlavní autoři: | , , , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
Elsevier Inc
01.06.2017
Elsevier |
| Témata: | |
| ISSN: | 0022-0000, 1090-2724 |
| On-line přístup: | Získat plný text |
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| Shrnutí: | •We design FPT-algorithms for the following two parameterized problems:•List Digraph Homomorphism, which is a “list” version of the classical Digraph Homomorphism problem.•Min-Max Multiway Cut, which is a variant of Multiway Cut.•We introduce a general problem, List Allocation, and we present parameterized reductions of both aforementioned problems to it.•We provide an FPT-algorithm for the List Allocation adapting of the randomized contractions technique introduced by Chitnis et al. (2012).
We design FPT-algorithms for the following problems. The first is List Digraph Homomorphism: given two digraphs G and H, with order n and h, respectively, and a list of allowed vertices of H for every vertex of G, does there exist a homomorphism from G to H respecting the list constraints? Let ℓ be the number of edges of G mapped to non-loop edges of H. The second problem is Min-Max Multiway Cut: given a graph G, an integer ℓ≥0, and a set T of r terminals, can we partition V(G) into r parts such that each part contains one terminal and there are at most ℓ edges with only one endpoint in this part? We solve both problems in time 2O(ℓ⋅logh+ℓ2⋅logℓ)⋅n4⋅logn and 2O((ℓr)2logℓr)⋅n4⋅logn, respectively, via a reduction to a new problem called List Allocation, which we solve adapting the randomized contractions technique of Chitnis et al. (2012) [4]. |
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| ISSN: | 0022-0000 1090-2724 |
| DOI: | 10.1016/j.jcss.2017.01.003 |