In [19] Huang gave a characterization of local tournaments. His characterization involves arc-reversals and therefore may not be easily used to solve other structural problems on locally semicompleteâ€¦ (More)

In this paper we present some new sufficient conditions for equality of edge-connectivity and minimum degree of graphs and digraphs as well as of bipartite graphs and digraphs.

A subset S of vertices in a graph G is a called a geodetic dominating set if S is both a geodetic set and a (standard) dominating set. In this paper, we study geodetic domination on graphs.

A Roman dominating function on a graph G is a function f : V (G) â†’ {0, 1, 2} satisfying the condition that every vertex u for which f(u) = 0 is adjacent to at least one vertex v for which f(v) = 2.â€¦ (More)

In 1985, Fink and Jacobson gave a generalization of the concepts of domination and independence in graphs. For a positive integer k, a subset S of vertices in a graph G = (V, E) is k-dominating ifâ€¦ (More)