A note on vertex colorings of plane graphs

A note on vertex-edge Wiener indices of graphs

The vertex-edge Wiener index of a simple connected graph G is defined as the sum of distances between vertices and edges of G. Two possible distances D_1(u,e|G) and D_2(u,e|G) between a vertex u and an edge e of G were considered in the literature and according to them, the corresponding vertex-edge Wiener indices W_{ve_1}(G) and W_{ve_2}(G) were introduced. In this paper, we present exact form...

Strong parity vertex coloring of plane graphs

Czap and Jendrol’ introduced the notions of strong parity vertex coloring and the corresponding strong parity chromatic number χs. They conjectured that there is a constant bound K on χs for the class of 2-connected plane graphs. We prove that the conjecture is true with K = 97, even with an added restriction to proper colorings. Next, we provide simple examples showing that the sharp bound is ...

On Fall Colorings of Kneser Graphs

A fall k-coloring of a graph G is a proper k-coloring of G such that each vertex of G sees all k colors on its closed neighborhood. In this note, we characterize all fall colorings of Kneser graphs of type KG(n, 2) for n ≥ 2 and study some fall colorings of KG(n,m) in some special cases and introduce some bounds for fall colorings of Kneser graphs.

On the Defining Number of (2n - 2)-Vertex Colorings of Kn x Kn

A note on Grundy colorings of central graphs

A Grundy coloring of a graph G is a proper vertex coloring of G where any vertex x, colored with c(x), has a neighbor of any color 1, 2, . . . , c(x)− 1. A central graph Gc is obtained from G by adding an edge between any two non adjacent vertices in G and subdividing any edge of G once. In this note we focus on Grundy colorings of central graphs. We present some bounds related to parameters of...