An equitable graph coloring is a proper vertex coloring, such that the size of the color classes differ by at most one. We present a flow-based scheme for generating pruning rules for enumerative algorithms such as DSATUR. The scheme models the extendability of a partial (equitable) coloring into an equitable coloring via network flows. Computational experiments show that significant reductions...

Given a graph G= (V,E), a greedy coloring of G is a proper coloring such that, for each two colors i< j, every vertex of V (G) colored j has a neighbor with color i. The greatest k such that G has a greedy coloring with k colors is the Grundy number of G. A b-coloring of G is a proper coloring such that every color class contains a vertex which is adjacent to at least one vertex in every other ...

Graph coloring is a central problem in distributed computing. Both vertexand edge-coloring problems have been extensively studied in this context. In this paper we show that a (2∆ − 1)-edge-coloring can be computed in time smaller than log n for any > 0, specifically, in e √ log logn) rounds. This establishes a separation between the (2∆− 1)-edge-coloring and the Maximal Matching problems, as t...

We show for every k ≥ 1 that the binomial tree of order 3k has a vertex-coloring with 2k+1 colors such that every path contains some color odd number of times. This disproves a conjecture from [1] asserting that for every tree T the minimal number of colors in a such coloring of T is at least the vertex ranking number of T minus one.

A proper vertex k-coloring of a graph G is dynamic if for every vertex v with degree at least 2, the neighbors of v receive at least two different colors. The smallest integer k such that G has a dynamic k-coloring is the dynamic chromatic number χd(G). In this paper the differences betweenχd(G) andχd(G−e), and betweenχd(G) andχd(G−v) are investigated respectively. © 2016 Elsevier B.V. All righ...

A mixed hypergraph H = (X, C,D) consists of the vertex set X and two families of subsets: the family C of C-edges and the family D of D-edges. In a coloring, every C-edge has at least two vertices of common color, while every D-edge has at least two vertices of different colors. The largest (smallest) number of colors for which a coloring of a mixed hypergraph H using all the colors exists is c...

An edge coloring of a graph is a local r coloring if the edges incident to any vertex are colored with at most r distinct colors. We determine the size of the largest monochromatic component that must occur in any local r coloring of a complete graph or a complete bipartite graph. © 2007 Elsevier B.V. All rights reserved.