The union of minimal hitting sets: parameterized combinatorial bounds and counting
Artikel i vetenskaplig tidskrift, 2009

A k-hitting set in a hypergraph is a set of at most k vertices that intersects all hyperedges. We study the union of all inclusion-minimal k-hitting sets in hypergraphs of rank r (where the rank is the maximum size of hyperedges). We show that this union is relevant for certain combinatorial inference problems and give worst-case bounds on its size, depending on r and k. For r=2 our result is tight, and for each r>2 we have an asymptotically optimal bound and make progress regarding the constant factor. The exact worst-case size for r>2 remains an open problem. We also propose an algorithm for counting all k-hitting sets in hypergraphs of rank r. Its asymptotic runtime matches the best one known for the much more special problem of finding one k-hitting set. The results are used for efficient counting of k-hitting sets that contain any particular vertex.


hypergraph transversal

combinatorial inference




Peter Damaschke

Chalmers, Data- och informationsteknik, Datavetenskap

Leonid Molokov

Chalmers, Data- och informationsteknik, Datavetenskap

Journal of Discrete Algorithms

1570-8667 (ISSN)

Vol. 7 4 391-401


Datavetenskap (datalogi)

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