In the paper we show that all combinatorial triangle-free configurations for v ≤ 18 are geometrically realizable. We also show that there is a unique smallest astral (183) triangle-free configuration and its Levi graph is the generalized Petersen graph G(18, 5). In addition, we present geometric realizations of the unique flag transitive triangle-free configuration (203) and the unique point tr...

In this article we introduce the cylindrical construction, as an edge-replacement procedure admitting twists on both ends of the hyperedges, generalizing the concepts of lifts and Pultr templates at the same time. We prove a tensor-hom duality for this construction and we show that not only a large number of well-known graph constructions are cylindrical but also the construction and its dual g...

Isometric subgraphs of hypercubes are known as partial cubes. The subdivision graph of a graph G is obtained from G by subdividing every edge of G. It is proved that for a connected graph G its subdivision graph is a partial cube if and only if every block of G is either a cycle or a complete graph. Regular partial cubes are also considered. In particular it is shown that among the generalized ...

Robertson (1968) and independently, Bondy (1972) proved that the generalized Petersen graph P (n, 2) is non-hamiltonian if n ≡ 5 (mod 6) while Thomason (1982) proved that it has precisely three hamiltonian cycles if n ≡ 3 (mod 6). Here we give a unified proof (which is easier) of these results using Grinberg’s theorem.

A set S of vertices in a graph G is a double total dominating set, abbreviated DTDS, of G if every vertex of G is adjacent to least two vertices in S. The minimum cardinality of a DTDS of G is the double total domination number of G. In this paper, we study the DTDS of the generalized Petersen graphs. Mathematics Subject Classification: 05C35

We give a new proof that the Petersen graph is not 3-edge-colorable. J. Petersen introduced the most well known graph, the Petersen graph, as an example of a cubic bridgeless graph that is not Tait colorable, i.e. it is not 3-edge-colorable. It is easy to see the equivalence between the following statements, but most proofs for each of them use a case by case argument [1]. Theorem 1 For the Pet...

Motivated by a problem on message routing in communication networks, Graham and Pollak proposed a scheme for addressing the vertices of a graph G by N -tuples of three symbols in such a way that distances between vertices may readily be determined from their addresses. They observed that N ≥ h(D), the maximum of the number of positive and the number of negative eigenvalues of the distance matri...

The local antimagic total vertex labeling of graph G is a that every vertices and edges label by natural number from 1 to such two adjacent has different weights, where sum the labels all incident vertex. If start smallest then edge so kind coloring called super labeling. That induces for v, weight w(v) color v. minimum colors obtained chromatic G, denoted χlsat(G). In this paper, we consider G...