Set vertex colorings and joins of graphs

Futaba Okamoto; Craig W. Rasmussen; Ping Zhang

Czechoslovak Mathematical Journal (2009)

  • Volume: 59, Issue: 4, page 929-941
  • ISSN: 0011-4642

Abstract

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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 and upper bounds are established for χ s ( G + H ) in terms of χ s ( G ) , χ s ( H ) , and the clique numbers ω ( G ) and ω ( H ) .

How to cite

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Okamoto, Futaba, Rasmussen, Craig W., and Zhang, Ping. "Set vertex colorings and joins of graphs." Czechoslovak Mathematical Journal 59.4 (2009): 929-941. <http://eudml.org/doc/37967>.

@article{Okamoto2009,
abstract = {For a nontrivial connected graph $G$, let $c\: V(G)\rightarrow \mathbb \{N\}$ be a vertex coloring of $G$ where adjacent vertices may be colored the same. For a vertex $v$ of $G$, the neighborhood color set $\{\rm NC\}(v)$ is the set of colors of the neighbors of $v$. The coloring $c$ is called a set coloring if $\{\rm NC\}(u)\ne \{\rm NC\}(v)$ 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 $\chi _s(G)$. A study is made of the set chromatic number of the join $G + H$ of two graphs $G$ and $H$. Sharp lower and upper bounds are established for $\chi _s(G+H)$ in terms of $\chi _s(G)$, $\chi _s(H)$, and the clique numbers $\omega (G)$ and $\omega (H)$.},
author = {Okamoto, Futaba, Rasmussen, Craig W., Zhang, Ping},
journal = {Czechoslovak Mathematical Journal},
keywords = {neighbor-distinguishing coloring; set coloring; neighborhood color set; neighbour-distinguishing colouring; set colouring; neighbourhood colour set},
language = {eng},
number = {4},
pages = {929-941},
publisher = {Institute of Mathematics, Academy of Sciences of the Czech Republic},
title = {Set vertex colorings and joins of graphs},
url = {http://eudml.org/doc/37967},
volume = {59},
year = {2009},
}

TY - JOUR
AU - Okamoto, Futaba
AU - Rasmussen, Craig W.
AU - Zhang, Ping
TI - Set vertex colorings and joins of graphs
JO - Czechoslovak Mathematical Journal
PY - 2009
PB - Institute of Mathematics, Academy of Sciences of the Czech Republic
VL - 59
IS - 4
SP - 929
EP - 941
AB - For a nontrivial connected graph $G$, let $c\: V(G)\rightarrow \mathbb {N}$ be a vertex coloring of $G$ where adjacent vertices may be colored the same. For a vertex $v$ of $G$, the neighborhood color set ${\rm NC}(v)$ is the set of colors of the neighbors of $v$. The coloring $c$ is called a set coloring if ${\rm NC}(u)\ne {\rm NC}(v)$ 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 $\chi _s(G)$. A study is made of the set chromatic number of the join $G + H$ of two graphs $G$ and $H$. Sharp lower and upper bounds are established for $\chi _s(G+H)$ in terms of $\chi _s(G)$, $\chi _s(H)$, and the clique numbers $\omega (G)$ and $\omega (H)$.
LA - eng
KW - neighbor-distinguishing coloring; set coloring; neighborhood color set; neighbour-distinguishing colouring; set colouring; neighbourhood colour set
UR - http://eudml.org/doc/37967
ER -

References

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  1. Chartrand, G., Okamoto, F., Rasmussen, C. W., Zhang, P., The set chromatic number of a graph, Discuss. Math. Graph Theory (to appear). MR2642800
  2. Chartrand, G., Zhang, P., Chromatic Graph Theory, Chapman & Hall/CRC Press Boca Raton (2008). (2008) MR2450569

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