In social networks, a role assignment is such that individuals play the same role, if they relate in way to other playing counterpart roles. As simple graph models network rises decision problem called r -Role Assignment whether it exists an of distinct roles vertices graph. This known be NP-complete for any fixed ? 2. The Cartesian product graphs one most studied operation on and has numerous ...

The vertices of the flag graph Φ(P ) of a graded poset P are its maximal chains. Two vertices are adjacent whenever two maximal chains differ in exactly one element. In this paper we characterize induced subgraphs of Cartesian product graphs and flag graphs of graded posets. The latter class of graphs lies between isometric and induced subgraphs of Cartesian products in the embedding structure ...

Under suitable conditions of connectivity or non-bipartiteness, each of the three standard graph products (the Cartesian product, the direct product and the strong product) satisfies the unique prime factorization property, and there are polynomial algorithms to determine the prime factors. This is most easily proved for the Cartesian product. For the other products, current proofs involve a no...

In this paper, we design an algorithm that, given a directed graph G and the Cartesian-product decomposition of its underlying undirected graph G̃, produces the directed Cartesian-product decomposition of G in linear time. This is the first time that the linear complexity is achieved for this problem, which has two major consequences. Firstly, it shows that the directed and undirected versions o...

If each minimal dominating set in a graph is minimum set, then the called well-dominated. Since seminal paper on well-dominated graphs appeared 1988, structure of from several restricted classes has been studied. In this we give complete characterization nontrivial direct products that are We prove if strong product well-dominated, both its factors When one graph, other factor being also suffic...

This paper is concerned with the fast computation of a relation d on the edge set of connected graphs that plays a decisive role in the recognition of approximate Cartesian products, the weak reconstruction of Cartesian products, and the recognition of Cartesian graph bundles with a triangle free basis. A special case of d is the relation δ, whose convex closure yields the product relation σ th...

This paper concerns finite, edge-transitive direct and strong products, as well as infinite weak Cartesian products. We prove that the direct product of two connected, non-bipartite graphs is edge-transitive if and only if both factors are edgetransitive and at least one is arc-transitive, or one factor is edge-transitive and the other is a complete graph with loops at each vertex. Also, a stro...