Displaying similar documents to “Transitive Hall sets.”

Edge-Transitive Lexicographic and Cartesian Products

Wilfried Imrich, Ali Iranmanesh, Sandi Klavžar, Abolghasem Soltani (2016)

Discussiones Mathematicae Graph Theory

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In this note connected, edge-transitive lexicographic and Cartesian products are characterized. For the lexicographic product G ◦ H of a connected graph G that is not complete by a graph H, we show that it is edge-transitive if and only if G is edge-transitive and H is edgeless. If the first factor of G ∘ H is non-trivial and complete, then G ∘ H is edge-transitive if and only if H is the lexicographic product of a complete graph by an edgeless graph. This fixes an error of Li, Wang,...

Transitive closure and transitive reduction in bidirected graphs

Ouahiba Bessouf, Abdelkader Khelladi, Thomas Zaslavsky (2019)

Czechoslovak Mathematical Journal

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In a bidirected graph, an edge has a direction at each end, so bidirected graphs generalize directed graphs. We generalize the definitions of transitive closure and transitive reduction from directed graphs to bidirected graphs by introducing new notions of bipath and bicircuit that generalize directed paths and cycles. We show how transitive reduction is related to transitive closure and to the matroids of the signed graph corresponding to the bidirected graph.