In many geographical applications there is a need to model spatial phenomena not simply by sharp objects but rather through indeterminate or vague concepts. To support such applications we present a model of vague regions which covers and extends previous approaches. The formal framework is based on a general exact model of spatial data types. On the one hand, this simplifies the definition of ...

This paper is devoted to the study of double domination in vague graphs, and it a contribution Special Issue “Advances graph theory Symmetry/Asymmetry” Symmetry. Symmetry one most important criteria that illustrate structure properties fuzzy graphs. It has many applications dominating sets helps find suitable place for construction. Vague graphs (VGs), which are family (FGs), well-organized use...

A graph is said to be S-prime if, whenever it is a subgraph of a nontrivial Cartesian product graph, it is a subgraph of one of the factors. A diagonalized Cartesian product is obtained from a Cartesian product graph by connecting two vertices of maximal distance by an additional edge. We show there that a diagonalized product of S-prime graphs is again S-prime. Klavžar et al. [Discr. Math. 244...

Those graph products of groups that are virtually-free are characterized.