A k-edge-weighting w of a graph G is an assignment of an integer weight, w(e) ∈ {1, . . . , k}, to each edge e. An edge weighting naturally induces a vertex coloring c by defining c(u) = ∑ u∼e w(e) for every u ∈ V (G). A k-edge-weighting of a graph G is vertexcoloring if the induced coloring c is proper, i.e., c(u) ≠ c(v) for any edge uv ∈ E(G). Given a graph G and a vertex coloring c0, does th...

Let G be an edge-colored graph. A heterochromatic (rainbow, or multicolored) path of G is such a path in which no two edges have the same color. Let CN(v) denote the color neighborhood of a vertex v of G. In a previous paper, we showed that if |CN(u)∪CN(v)| ≥ s (color neighborhood union condition) for every pair of vertices u and v of G, then G has a heterochromatic path of length at least b 2s...

We study edge coloring games defining the so-called game chromatic index of a graph. It has been reported that the game chromatic index of trees with maximum degree ∆ = 3 is at most ∆ + 1. We show that the same holds true in case ∆ ≥ 6, which would leave only the cases ∆ = 4 and ∆ = 5 open.

An edge-coloring of a graph G with natural numbers is called a sum edge-coloring if the colors of edges incident to any vertex of G are distinct and the sum of the colors of the edges of G is minimum. The edge-chromatic sum of a graph G is the sum of the colors of edges in a sum edge-coloring of G. It is known that the problem of finding the edge-chromatic sum of an r-regular (r ≥ 3) graph is N...

Let H be a hypergraph. For a k-edge coloring c : E(H) → {1, . . . , k} let f(H, c) be the number of components in the subhypergraph induced by the color class with the least number of components. Let fk(H) be the maximum possible value of f(H, c) ranging over all k-edge colorings of H . If H is the complete graph Kn then, trivially, f1(Kn) = f2(Kn) = 1. In this paper we prove that for n ≥ 6, f3...

We study a local version of gap vertex-distinguishing edge coloring. From an edge labeling f : E(G) → {1, . . . , k} of a graph G, an induced vertex coloring c is obtained by coloring the vertices with the greatest difference between incident edge labels. The local gap chromatic number χ∆(G) is ∗ Partially funded by NSF GK-12 Transforming Experiences Grant DGE-0742434. † Partially funded by Sim...

The paper is devoted to the model of compact cyclic edge-coloring. This variant of edge-coloring finds its applications in modeling schedules in production systems, in which production proceeds in a cyclic way. We point out optimal colorings for some graph classes and we construct graphs which cannot be colored in a compact cyclic manner. Moreover, we prove some theoretical properties of consid...