The basis number b(G) of a graph G is defined to be the least integer d such that G has a d-fold basis for its cycle space. In this paper we: give an upper bound of the basis number of the direct product of trees; classify the trees with respect to the basis number of the direct product of trees and paths of order greater than or equal to 5; give an upper bound of the basis number of the direct...

Let S be a set of transpositions generating the symmetric group Sn, where n ≥ 3. It is shown that if the girth of the transposition graph of S is at least 5, then the automorphism group of the Cayley graph Cay(Sn, S) is the direct product Sn×Aut(T (S)), where T (S) is the transposition graph of S; the direct factors are the right regular representation of Sn and the image of the left regular ac...

Nathanson was the pioneer in introducing the concepts of Number Theory, particularly, the "Theory of Congruences" in Graph Theory, thus paving way for the emergence of a new class of graphs, namely "Arithmetic Graphs". Cayley graphs are another class of graphs associated with the elements of a group. If this group is associated with some arithmetic function then the Cayley g...

Rosenbloom and Tsfasman introduced a new metric (RT metric) which is a generalization of the Hamming metric. In this paper we study the distance graphs of spaces Zn q and Sn with Rosenbloom -Tsfasman metric. We also describe the degrees of vertices, components and the chromatic number of these graphs. Distance graphs of general direct product spaces also described.

There are four standard products of graphs: the direct product, the Cartesian product, the strong product and the lexicographic product. The chromatic number turned out to be an interesting parameter on all these products, except on the Cartesian one. A survey is given on the results concerning the chromatic number of the three relevant products. Some applications of product colorings are also ...

Let (G) be the domination number of a graph G, and let G H be the direct product of graphs G and H. It is shown that for any k 0 there exists a graph G such that (G G) (G) 2 ? k. This in particular disproves a conjecture from 5].

We are motivated by the following question concerning the direct product of graphs. If A×C ∼= B×C , what can be said about the relationship betweenA and B? If cancellation fails, what properties must A and B share?We define a structural equivalence relation∼ (called similarity) on graphs, weaker than isomorphism, for which A× C ∼= B× C implies A ∼ B. Thus cancellation holds, up to similarity. M...