Lower bounds on signed edge total domination numbers in graphs

H. Karami; S. M. Sheikholeslami; Abdollah Khodkar

Czechoslovak Mathematical Journal (2008)

  • Volume: 58, Issue: 3, page 595-603
  • ISSN: 0011-4642

Abstract

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The open neighborhood N G ( e ) of an edge e in a graph G is the set consisting of all edges having a common end-vertex with e . Let f be a function on E ( G ) , the edge set of G , into the set { - 1 , 1 } . If x N G ( e ) f ( x ) 1 for each e E ( G ) , then f is called a signed edge total dominating function of G . The minimum of the values e E ( G ) f ( e ) , taken over all signed edge total dominating function f of G , is called the signed edge total domination number of G and is denoted by γ s t ' ( G ) . Obviously, γ s t ' ( G ) is defined only for graphs G which have no connected components isomorphic to K 2 . In this paper we present some lower bounds for γ s t ' ( G ) . In particular, we prove that γ s t ' ( T ) 2 - m / 3 for every tree T of size m 2 . We also classify all trees T with γ s t ' ( T ) = 2 - m / 3 .

How to cite

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Karami, H., Sheikholeslami, S. M., and Khodkar, Abdollah. "Lower bounds on signed edge total domination numbers in graphs." Czechoslovak Mathematical Journal 58.3 (2008): 595-603. <http://eudml.org/doc/37855>.

@article{Karami2008,
abstract = {The open neighborhood $N_G(e)$ of an edge $e$ in a graph $G$ is the set consisting of all edges having a common end-vertex with $e$. Let $f$ be a function on $E(G)$, the edge set of $G$, into the set $\lbrace -1, 1\rbrace $. If $ \sum _\{x\in N_G(e)\}f(x) \ge 1$ for each $e\in E(G)$, then $f$ is called a signed edge total dominating function of $G$. The minimum of the values $\sum _\{e\in E(G)\} f(e)$, taken over all signed edge total dominating function $f$ of $G$, is called the signed edge total domination number of $G$ and is denoted by $\gamma _\{st\}^\{\prime \}(G)$. Obviously, $\gamma _\{st\}^\{\prime \}(G)$ is defined only for graphs $G$ which have no connected components isomorphic to $K_2$. In this paper we present some lower bounds for $\gamma _\{st\}^\{\prime \}(G)$. In particular, we prove that $\gamma _\{st\}^\{\prime \}(T)\ge 2-m/3$ for every tree $T$ of size $m\ge 2$. We also classify all trees $T$ with $\gamma _\{st\}^\{\prime \}(T)=2-m/3$.},
author = {Karami, H., Sheikholeslami, S. M., Khodkar, Abdollah},
journal = {Czechoslovak Mathematical Journal},
keywords = {signed edge domination; signed edge total dominating function; signed edge total domination number; signed edge domination; signed edge total dominating function; signed edge total domination number},
language = {eng},
number = {3},
pages = {595-603},
publisher = {Institute of Mathematics, Academy of Sciences of the Czech Republic},
title = {Lower bounds on signed edge total domination numbers in graphs},
url = {http://eudml.org/doc/37855},
volume = {58},
year = {2008},
}

TY - JOUR
AU - Karami, H.
AU - Sheikholeslami, S. M.
AU - Khodkar, Abdollah
TI - Lower bounds on signed edge total domination numbers in graphs
JO - Czechoslovak Mathematical Journal
PY - 2008
PB - Institute of Mathematics, Academy of Sciences of the Czech Republic
VL - 58
IS - 3
SP - 595
EP - 603
AB - The open neighborhood $N_G(e)$ of an edge $e$ in a graph $G$ is the set consisting of all edges having a common end-vertex with $e$. Let $f$ be a function on $E(G)$, the edge set of $G$, into the set $\lbrace -1, 1\rbrace $. If $ \sum _{x\in N_G(e)}f(x) \ge 1$ for each $e\in E(G)$, then $f$ is called a signed edge total dominating function of $G$. The minimum of the values $\sum _{e\in E(G)} f(e)$, taken over all signed edge total dominating function $f$ of $G$, is called the signed edge total domination number of $G$ and is denoted by $\gamma _{st}^{\prime }(G)$. Obviously, $\gamma _{st}^{\prime }(G)$ is defined only for graphs $G$ which have no connected components isomorphic to $K_2$. In this paper we present some lower bounds for $\gamma _{st}^{\prime }(G)$. In particular, we prove that $\gamma _{st}^{\prime }(T)\ge 2-m/3$ for every tree $T$ of size $m\ge 2$. We also classify all trees $T$ with $\gamma _{st}^{\prime }(T)=2-m/3$.
LA - eng
KW - signed edge domination; signed edge total dominating function; signed edge total domination number; signed edge domination; signed edge total dominating function; signed edge total domination number
UR - http://eudml.org/doc/37855
ER -

References

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  1. Karami, H., Khodkar, A., Sheikholeslami, S. M., Signed edge domination numbers in trees, Ars Combinatoria (to appear). MR2568858
  2. West, D. B., Introduction to Graph Theory, Prentice-Hall, Inc (2000). (2000) MR1367739
  3. Xu, B., 10.1016/S0012-365X(01)00044-9, Discrete Mathematics 239 (2001), 179-189. (2001) Zbl0979.05081MR1850997DOI10.1016/S0012-365X(01)00044-9
  4. Xu, B., On lower bounds of signed edge domination numbers in graphs, J. East China Jiaotong Univ. 1 (2004), 110-114 Chinese. (2004) 
  5. Zelinka, B., On signed edge domination numbers of trees, Math. Bohem. 127 (2002), 49-55. (2002) Zbl0995.05112MR1895246

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