Displaying similar documents to “Defining sets in (proper) vertex colorings of the Cartesian product of a cycle with a complete graph”

Set vertex colorings and joins of graphs

Futaba Okamoto, Craig W. Rasmussen, Ping Zhang (2009)

Czechoslovak Mathematical Journal

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For a nontrivial connected graph G , let c V ( G ) 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 ) NC ( v ) for every pair u , v of adjacent vertices of G . The minimum number of colors required of such a coloring is called the set chromatic number χ s ( G ) . A study is made of the set chromatic number of the join G + H of two graphs G and H . Sharp lower...

A new upper bound for the chromatic number of a graph

Ingo Schiermeyer (2007)

Discussiones Mathematicae Graph Theory

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Let G be a graph of order n with clique number ω(G), chromatic number χ(G) and independence number α(G). We show that χ(G) ≤ [(n+ω+1-α)/2]. Moreover, χ(G) ≤ [(n+ω-α)/2], if either ω + α = n + 1 and G is not a split graph or α + ω = n - 1 and G contains no induced K ω + 3 - C .

On the dominator colorings in trees

Houcine Boumediene Merouane, Mustapha Chellali (2012)

Discussiones Mathematicae Graph Theory

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In a graph G, a vertex is said to dominate itself and all its neighbors. A dominating set of a graph G is a subset of vertices that dominates every vertex of G. The domination number γ(G) is the minimum cardinality of a dominating set of G. A proper coloring of a graph G is a function from the set of vertices of the graph to a set of colors such that any two adjacent vertices have different colors. A dominator coloring of a graph G is a proper coloring such that every vertex of V dominates...

Radio antipodal colorings of graphs

Gary Chartrand, David Erwin, Ping Zhang (2002)

Mathematica Bohemica

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A radio antipodal coloring of a connected graph G with diameter d is an assignment of positive integers to the vertices of G , with x V ( G ) assigned c ( x ) , such that d ( u , v ) + | c ( u ) - c ( v ) | d for every two distinct vertices u , v of G , where d ( u , v ) is the distance between u and v in G . The radio antipodal coloring number a c ( c ) of a radio antipodal coloring c of G is the maximum color assigned to a vertex of G . The radio antipodal chromatic number a c ( G ) of G is min { a c ( c ) } over all radio antipodal colorings c of G . Radio antipodal chromatic numbers...

On detectable colorings of graphs

Henry Escuadro, Ping Zhang (2005)

Mathematica Bohemica

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Let G be a connected graph of order n 3 and let c E ( G ) { 1 , 2 , ... , k } be a coloring of the edges of G (where adjacent edges may be colored the same). For each vertex v of G , the color code of v with respect to c is the k -tuple c ( v ) = ( a 1 , a 2 , , a k ) , where a i is the number of edges incident with v that are colored i ( 1 i k ). The coloring c is detectable if distinct vertices have distinct color codes. The detection number det ( G ) of G is the minimum positive integer k for which G has a detectable k -coloring. We establish a formula for the...

Radio k-colorings of paths

Gary Chartrand, Ladislav Nebeský, Ping Zhang (2004)

Discussiones Mathematicae Graph Theory

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For a connected graph G of diameter d and an integer k with 1 ≤ k ≤ d, a radio k-coloring of G is an assignment c of colors (positive integers) to the vertices of G such that d(u,v) + |c(u)- c(v)| ≥ 1 + k for every two distinct vertices u and v of G, where d(u,v) is the distance between u and v. The value rcₖ(c) of a radio k-coloring c of G is the maximum color assigned to a vertex of G. The radio k-chromatic number rcₖ(G) of G is the minimum value of rcₖ(c) taken over all radio k-colorings...

Multicolor Ramsey numbers for paths and cycles

Tomasz Dzido (2005)

Discussiones Mathematicae Graph Theory

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For given graphs G₁,G₂,...,Gₖ, k ≥ 2, the multicolor Ramsey number R(G₁,G₂,...,Gₖ) is the smallest integer n such that if we arbitrarily color the edges of the complete graph on n vertices with k colors, then it is always a monochromatic copy of some G i , for 1 ≤ i ≤ k. We give a lower bound for k-color Ramsey number R(Cₘ,Cₘ,...,Cₘ), where m ≥ 8 is even and Cₘ is the cycle on m vertices. In addition, we provide exact values for Ramsey numbers R(P₃,Cₘ,Cₚ), where P₃ is the path on 3 vertices,...