Institution: | a Instituto de Matemática and COPPE, Universidade Federal do Rio de Janeiro, Caixa Postal 68530, 21945-970, Rio de Janeiro, RJ, Brazil b Mathematical Sciences, University of Alaska, Fairbanks, Alaska 99775, USA c Instituto de Computação, Universidade Estadual de Campinas, Caixa Postal 6176, 13081-970, Campinas, SP, Brazil d Núcleo de Computação Eletrônica, Instituto de Matemática and COPPE, Universidade Federal do Rio de Janeiro, Caixa Postal 2324, 20001-970, Rio de Janeiro, RJ, Brazil |
Abstract: | Given a transitive orientation
of a comparability graph G, a vertex of G is a source (sink) if it has indegree (outdegree) zero in
, respectively. A source set of G is a subset of vertices formed by sources of some transitive orientation
. A pair of subsets S,TV(G) is a source–sink pair of G when the vertices of S and T are sources and sinks, of some transitive orientation
, respectively. We describe algorithms for finding a transitive orientation with a maximum source–sink pair in a comparability graph. The algorithms are applications of modular decomposition and are all of linear-time complexity. |