The usual Ramsey number R(G, k) is the smallest positive integer n such that any coloring of the edges of Kn by at most k colors contains a monochromatic copy of G. Over the past years several papers have been written in which the number of different colors used has no longer been restricted to k, but a restriction is placed on the number of colored edges incident to the vertices. To be precise...

Golovach, Paulusma and Song (Inf. Comput. 2014) asked to determine the parameterized complexity of following problems by k: (1) Given a graph G, clique modulator D (a is set vertices, whose removal results in clique) size k for list L(v) colors every v ∈ V(G), decide whether G has proper coloring; (2) pre-coloring λ_P: X → Q ⊆ λ_P can be extended coloring using only from Q. For Problem 1 we des...

An acyclic coloring of a graph G is a coloring of the vertices of G, where no two adjacent vertices of G receive the same color and no cycle of G is bichromatic. An acyclic k-coloring of G is an acyclic coloring of G using at most k colors. In this paper we prove that any triangulated plane graph G with n vertices has a subdivision that is acyclically 4-colorable, where the number of division v...

In a properly edge colored graph, a subgraph using every color at most once is called rainbow. In this thesis, we study rainbow cycles and paths in proper edge colorings of complete graphs, and we prove that in every proper edge coloring of Kn, there is a rainbow path on (3/4− o(1))n vertices, improving on the previously best bound of (2n + 1)/3 from [?]. Similarly, a k-rainbow path in a proper...

A Grundy k-coloring of a graph G, is a vertex k-coloring of G such that for each two colors i and j with i < j, every vertex of G colored by j has a neighbor with color i. The Grundy chromatic number Γ(G), is the largest integer k for which there exists a Grundy k-coloring for G. In this note we first give an interpretation of Γ(G) in terms of the total graph of G, when G is the complement of a...

A proper vertex coloring of a graphG is called a star-coloring if there is no path on four vertices assigned to two colors. The graph G is L-star-colorable if for a given list assignment L there is a star-coloring c such that c(v) ∈ L(v). If G is L-star-colorable for any list assignment L with |L(v)| ≥ k for all v ∈ V (G), then G is called k-star-choosable. The star list chromatic number of G, ...

Message passing algorithms are popular in many combinatorial optimization problems. Forexample, experimental results show that survey propagation (a certain message passing algorithm)is effective in finding proper k-colorings of random graphs in the near-threshold regime. Gallagerin 1962 introduced the concept of Low Density Parity Check (LDPC) codes, and suggested asimple d...

A k-coloring of G = (V,E) is a partition S = (S1, . . . , Sk) of the node set V of G into stable sets Si (a stable set is a set of pairwise non adjacent nodes). In the usual case, the objective is to determine a node coloring minimizing k. A natural generalization of this problem is obtained by assigning a strictly positive integer weight w(v) for any node v ∈ V , and defining the weight of sta...

The equitable tree-coloring can formulate a structure decomposition problem on the communication network with some security considerations. Namely, an tree-k-coloring of graph is vertex coloring using k distinct colors such that every color class induces forest and sizes any two classes differ by at most one. In this paper, we show theoretical results graphs proving d-degenerate maximum degree ...