Tree-width of hypergraphs and surface duality
Résumé
In Graph Minors III, Robertson and Seymour write:”It seems that the tree-width of a planar graph and the tree-width of its geometric dual are approximately equal — indeed, we have convinced ourselves that they differ by at most one.” They never gave a proof of this. In this paper, we prove that given a hypergraph H on a surface of Euler genus k, the tree-width of H^∗ is at most the maximum of tw(H)+1+k and the maximum size of a hyperedge of H^∗ minus one.
Domaines
Mathématique discrète [cs.DM]
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