منابع مشابه
The Chromatic Number of a Signed Graph
In 1982, Zaslavsky introduced the concept of a proper vertex colouring of a signed graph G as a mapping φ : V (G) → Z such that for any two adjacent vertices u and v the colour φ(u) is different from the colour σ(uv)φ(v), where is σ(uv) is the sign of the edge uv. The substantial part of Zaslavsky’s research concentrated on polynomial invariants related to signed graph colourings rather than on...
متن کاملtotal dominator chromatic number of a graph
given a graph $g$, the total dominator coloring problem seeks aproper coloring of $g$ with the additional property that everyvertex in the graph is adjacent to all vertices of a color class. weseek to minimize the number of color classes. we initiate to studythis problem on several classes of graphs, as well as findinggeneral bounds and characterizations. we also compare the totaldominator chro...
متن کاملThe set chromatic number of a graph
For a nontrivial connected graph G, let c : V (G) → N be a vertex coloring of G where adjacent vertices may be colored the same. For a vertex v of G, the neighborhood color set NC(v) is the set of colors of the neighbors of v. The coloring c is called a set coloring if NC(u) 6= NC(v) for every pair u, v of adjacent vertices of G. The minimum number of colors required of such a coloring is calle...
متن کاملDetermining the Chromatic Number of a Graph
Certain branch-and-bound algorithms for determining the chromatic number of a graph are proved usually to take a number of steps which grows faster than exponentially with the number of vertices in the graph. A similar result holds for the number of steps in certain proofs of lower bounds for chromatic numbers. Key words, graph, chromatic number, algorithm, proof
متن کاملThe String Chromatic Number of a Graph
It is shown that there is an absolute constant c with the following property: For any two graphs G1 = (V,E1) and G2 = (V,E2) on the same set of vertices, where G1 has maximum degree at most d and G2 is a vertex disjoint union of cliques of size cd each, the chromatic number of the graph G = (V,E1 ∪ E2) is precisely cd. The proof is based on probabilistic arguments.
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ژورنال
عنوان ژورنال: The Electronic Journal of Combinatorics
سال: 2016
ISSN: 1077-8926
DOI: 10.37236/4938