The cut polytope of a graph arises in many fields. Although much is known about facets of the cut polytope of the complete graph, very little is known for general graphs. The study of Bell inequalities in quantum information science requires knowledge of the facets of the cut polytope of the complete bipartite graph or, more generally, the complete k-partite graph. Lifting is a central tool to ...

Given a graph G = (V,E), an L(δ1, δ2, δ3)-labeling is a function f assigning to nodes of V colors from a set {0, 1, . . . , kf} such that |f(u) − f(v)| ≥ δi if u and v are at distance i in G. The aim of the L(δ1, δ2, δ3)-labeling problem consists of finding a coloring function f such that the value of kf is minimum. This minimum value is called λδ1,δ2,δ3(G). In this paper we study this problem ...

Using graph theoretic techniques, it is shown that the height characteristic of a triangular matrix A majorizes the dual sequence of the sequence of differences of maximal cardinalities of singular k-paths in the graph G(A) of A and that in the generic case the height characteristic is equal to that dual sequence. The results on matrices are also used to prove a graph theoretic result on the du...

Abstract: A graph G with p vertices is said to be strongly multiplicative if the vertices of G can be labeled with p consecutive positive integers 1, 2, ..., p such that label induced on the edges by the product of labels of end vertices are all distinct. In this paper we investigate strongly multiplicative labeling of some snake related graphs. We prove that alternate triangular snake and alte...

In this paper, we investigate the heat kernel embedding as a route to graph representation. The heat kernel of the graph encapsulates information concerning the distribution of path lengths and, hence, node affinities on the graph; and is found by exponentiating the Laplacian eigen-system over time. A Young–Householder decomposition is performed on the heat kernel to obtain the matrix of the em...

In this paper, we study the relationship between the Asymmetric Traveling Salesman Problem (ATSP) and the Cycle Cover Problem in terms of the strength of the triangle inequality on the edge costs in the given complete directed graph instance, G = (V, E). The strength of the triangle inequality is captured by parametrizing the triangle inequality as follows. A complete directed graph G = (V, E) ...

We study the Hamiltonian Cycle problem in graphs induced by subsets of the vertices of the tiling of the plane with equilateral triangles. By analogy with grid graphs we call such graphs triangular grid graphs. Following the analogy, we define the class of solid triangular grid graphs. We prove that the Hamiltonian Cycle problem is NPcomplete for triangular grid graphs. We show that with the ex...