Displaying similar documents to “Recognizable colorings of graphs”

The multiset chromatic number of a graph

Gary Chartrand, Futaba Okamoto, Ebrahim Salehi, Ping Zhang (2009)

Mathematica Bohemica

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A vertex coloring of a graph G is a multiset coloring if the multisets of colors of the neighbors of every two adjacent vertices are different. The minimum k for which G has a multiset k -coloring is the multiset chromatic number χ m ( G ) of G . For every graph G , χ m ( G ) is bounded above by its chromatic number χ ( G ) . The multiset chromatic number is determined for every complete multipartite graph as well as for cycles and their squares, cubes, and fourth powers. It is conjectured that for each k 3 , there...

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...

Recognizable colorings of cycles and trees

Michael J. Dorfling, Samantha Dorfling (2012)

Discussiones Mathematicae Graph Theory

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For a graph G and a vertex-coloring c:V(G) → 1,2, ...,k, the color code of a vertex v is the (k+1)-tuple (a₀,a₁, ...,aₖ), where a₀ = c(v), and for 1 ≤ i ≤ k, a i is the number of neighbors of v colored i. A recognizable coloring is a coloring such that distinct vertices have distinct color codes. The recognition number of a graph is the minimum k for which G has a recognizable k-coloring. In this paper we prove three conjectures of Chartrand et al. in [8] regarding the recognition number...

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 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 stratification and domination in graphs

Ralucca Gera, Ping Zhang (2006)

Discussiones Mathematicae Graph Theory

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A graph G is 2-stratified if its vertex set is partitioned into two classes (each of which is a stratum or a color class), where the vertices in one class are colored red and those in the other class are colored blue. Let F be a 2-stratified graph rooted at some blue vertex v. An F-coloring of a graph is a red-blue coloring of the vertices of G in which every blue vertex v belongs to a copy of F rooted at v. The F-domination number γ F ( G ) is the minimum number of red vertices in an F-coloring...