Akers et al. (Proceedings of the International Conference on Parallel Processing, 1987, pp. 393–400) proposed an interconnection topology, the star graph, as an alternative to the popular n-cube. Jwo et al. (Networks 23 (1993) 315–326) studied the alternating group graph An. Cheng et al. (Super connectivity of star graphs, alternating group graphs and split-stars, Ars Combin. 59 (2001) 107–116)...

A star coloring of a graph is a proper coloring such that no path on four vertices is 2-colored. We prove that every planar graph with girth at least 9 can be star colored using 5 colors, and that every planar graph with girth at least 14 can be star colored using 4 colors; the figure 4 is best possible. We give an example of a girth 7 planar graph that requires 5 colors to star color.

A star-factor of a graph G is a spanning subgraph of G such that each of its component is a star. Clearly, every graph without isolated vertices has a star factor. A graph G is called star-uniform if all star-factors of G have the same number of components. To characterize star-uniform graphs was an open problem posed by Hartnell and Rall, which is motivated by the minimum cost spanning tree an...

An extended star is a tree which has only one vertex with degree larger than two. The -center problem in a graph  asks to find a subset  of the vertices of  of cardinality  such that the maximum weighted distances from  to all vertices is minimized. In this paper we consider the -center problem on the unweighted extended stars, and present some properties to find solution.

The annihilating-ideal graph of a commutative ring $R$ is denoted by $AG(R)$, whose vertices are all nonzero ideals of $R$ with nonzero annihilators and two distinct vertices $I$ and $J$ are adjacent if and only if $IJ=0$. In this article, we completely characterize rings $R$ when $gr(AG(R))neq 3$.

A star coloring of a graph is a proper vertex-coloring such that no path on four vertices is 2-colored. We prove that the vertices of every bipartite planar graph can be star colored from lists of size 14, and we give an example of a bipartite planar graph that requires at least 8 colors to star color.

A star coloring of a graph is a proper vertex-coloring such that no path on four vertices is 2-colored. We prove that the vertices of every planar graph of girth 6 (respectively 7,8) can be star colored from lists of size 8 (respectively 7,6). We give an example of a planar graph of girth 5 that requires 6 colors to star color.

In this paper, we aim to embed a longest path between every two vertices of a star graph with at most n-3 random edge faults, where n is the dimension of the star graph. Since the star graph is regular of degree n1, n-3 (edge faults) is maximum in the worst case. We show that when n≥6 and there are n-3 edge faults, the star graph can embed a longest path between every two vertices, exclusive of...