Repositori URV

Identificador: PC:513

Handle: https://hdl.handle.net/20.500.11797/PC513

Autors:
Rodriguez-Velazquez, J.A.Yero, I.G.

Resum:
A global boundary defensive k-alliance in a graph G = (V, E) is a dominating set S of vertices of G with the property that every vertex in 5 has fc more neighbors in 5 than it has outside of S. A global boundary offensive fc-alliance in a graph G is a set S of vertices of G with the property that every vertex in V - S has fc more neighbors in S than it has outside of S. We define a global boundary powerful fc-alliance as a set 5 of vertices of G, which is both global boundary defensive kalliance and global boundary offensive (k + 2)-alliance. In this paper we study mathematical properties of boundary powerful k-alliances. In particular, we obtain several bounds (closed formulas for the case of regular graphs) on the cardinality of every global boundary powerful k-alliance. In addition, we consider the case in which the vertex set of a graph G can be partitioned' into two boundary powerful fcalliances, showing that, in such a case, k = - 1 and, if G is amp;d-regular, its algebraic connectivity is equal to amp;d +1.