scholarly journals Independent Domination Stable Trees and Unicyclic Graphs

Mathematics ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 820
Author(s):  
Pu Wu ◽  
Huiqin Jiang ◽  
Sakineh Nazari-Moghaddam ◽  
Seyed Mahmoud Sheikholeslami ◽  
Zehui Shao ◽  
...  

A set S ⊆ V ( G ) in a graph G is a dominating set if every vertex of G is either in S or adjacent to a vertex of S . A dominating set S is independent if any pair of vertices in S is not adjacent. The minimum cardinality of an independent dominating set on a graph G is called the independent domination number i ( G ) . A graph G is independent domination stable if the independent domination number of G remains unchanged under the removal of any vertex. In this paper, we study the basic properties of independent domination stable graphs, and we characterize all independent domination stable trees and unicyclic graphs. In addition, we establish bounds on the order of independent domination stable trees.

2015 ◽  
Vol 23 (2) ◽  
pp. 187-199
Author(s):  
C. Natarajan ◽  
S.K. Ayyaswamy

Abstract Let G = (V;E) be a graph. A set S ⊂ V (G) is a hop dominating set of G if for every v ∈ V - S, there exists u ∈ S such that d(u; v) = 2. The minimum cardinality of a hop dominating set of G is called a hop domination number of G and is denoted by γh(G). In this paper we characterize the family of trees and unicyclic graphs for which γh(G) = γt(G) and γh(G) = γc(G) where γt(G) and γc(G) are the total domination and connected domination numbers of G respectively. We then present the strong equality of hop domination and hop independent domination numbers for trees. Hop domination numbers of shadow graph and mycielskian graph of graph are also discussed.


Mathematics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 194 ◽  
Author(s):  
Abel Cabrera-Martínez ◽  
Juan Carlos Hernández-Gómez ◽  
Ernesto Parra-Inza ◽  
José María Sigarreta Almira

A set of vertices of a graph G is a total dominating set if every vertex of G is adjacent to at least one vertex in such a set. We say that a total dominating set D is a total outer k-independent dominating set of G if the maximum degree of the subgraph induced by the vertices that are not in D is less or equal to k − 1 . The minimum cardinality among all total outer k-independent dominating sets is the total outer k-independent domination number of G. In this article, we introduce this parameter and begin with the study of its combinatorial and computational properties. For instance, we give several closed relationships between this novel parameter and other ones related to domination and independence in graphs. In addition, we give several Nordhaus–Gaddum type results. Finally, we prove that computing the total outer k-independent domination number of a graph G is an NP-hard problem.


Author(s):  
Ammar Babikir ◽  
Magda Dettlaff ◽  
Michael A. Henning ◽  
Magdalena Lemańska

AbstractA set S of vertices in a graph G is a dominating set if every vertex not in S is ad jacent to a vertex in S. If, in addition, S is an independent set, then S is an independent dominating set. The independent domination number i(G) of G is the minimum cardinality of an independent dominating set in G. The independent domination subdivision number $$ \hbox {sd}_{\mathrm{i}}(G)$$ sd i ( G ) is the minimum number of edges that must be subdivided (each edge in G can be subdivided at most once) in order to increase the independent domination number. We show that for every connected graph G on at least three vertices, the parameter $$ \hbox {sd}_{\mathrm{i}}(G)$$ sd i ( G ) is well defined and differs significantly from the well-studied domination subdivision number $$\mathrm{sd_\gamma }(G)$$ sd γ ( G ) . For example, if G is a block graph, then $$\mathrm{sd_\gamma }(G) \le 3$$ sd γ ( G ) ≤ 3 , while $$ \hbox {sd}_{\mathrm{i}}(G)$$ sd i ( G ) can be arbitrary large. Further we show that there exist connected graph G with arbitrarily large maximum degree $$\Delta (G)$$ Δ ( G ) such that $$ \hbox {sd}_{\mathrm{i}}(G) \ge 3 \Delta (G) - 2$$ sd i ( G ) ≥ 3 Δ ( G ) - 2 , in contrast to the known result that $$\mathrm{sd_\gamma }(G) \le 2 \Delta (G) - 1$$ sd γ ( G ) ≤ 2 Δ ( G ) - 1 always holds. Among other results, we present a simple characterization of trees T with $$ \hbox {sd}_{\mathrm{i}}(T) = 1$$ sd i ( T ) = 1 .


Let G be the graph, consider the vertex set as V and edge set as E. If S is the subset of the vertex set V such that S contains vertices which has atleast one neighbor in V that is not in S, then S is said to be dominating set of G. If the vertex in S is not adjacent to one another, then S is called as the independent dominating set of G and so i(G) represents the independent domination number, the minimum cardinality of an independent dominating set in G. In this paper, we obtain independent domination number for triangular, quadrilateral, pentagonal, hexagonal, heptagonal and octagonal networks by Adaptive Mesh Refinement (AMR)-WENO Scheme.


Let V be the vertex set and E be the edge set of a graph G, the vertex set V has a subset S such that S contains vertices which is adjacent to atleast one vertex in V which is not in S, then S is said to be dominating set of G. If the vertex in S is not adjacent to each other, then S is said to be independent dominating set of G and so i(G) denotes the independent domination number, the minimum cardinality of an independent dominating set in G. In this paper, we obtain independent domination number for a triangular snake, alternate triangular snake, double triangular snake, alternate double triangular snake, quadrilateral snake, alternate quadrilateral snake, double quadrilateral snake and alternate double quadrilateral snake graphs.


2020 ◽  
Vol 9 (11) ◽  
pp. 9335-9339
Author(s):  
N. Senthurpriya ◽  
S. Meenakshi ◽  
P. Punithavathi

Let G(V,E) be a graph, V has a subset C, this set is an non-empty subset of V and the vertices in C is adjacent to the minimum of one vertex of the set V, then G has the dominating set C. If there is no adjacency between the vertices of C, then G has an independent dominating set C and so the number of vertices present in the set C represents the IDN, the minimum cardinality of the sets C. Here in our research, we find the same for some special networks, namely the polygons with nine, ten and eleven sides by above mentioned Scheme.


2018 ◽  
Vol 10 (02) ◽  
pp. 1850024
Author(s):  
Nuttawoot Nupo ◽  
Sayan Panma

Let [Formula: see text] denote the Cayley digraph of the rectangular group [Formula: see text] with respect to the connection set [Formula: see text] in which the rectangular group [Formula: see text] is isomorphic to the direct product of a group, a left zero semigroup, and a right zero semigroup. An independent dominating set of [Formula: see text] is the independent set of elements in [Formula: see text] that can dominate the whole elements. In this paper, we investigate the independent domination number of [Formula: see text] and give more results on Cayley digraphs of left groups and right groups which are specific cases of rectangular groups. Moreover, some results of the path independent domination number of [Formula: see text] are also shown.


10.37236/847 ◽  
2008 ◽  
Vol 15 (1) ◽  
Author(s):  
Odile Favaron

A dominating set $S$ of a graph $G$ is a global (strong) defensive alliance if for every vertex $v\in S$, the number of neighbors $v$ has in $S$ plus one is at least (greater than) the number of neighbors it has in $V\setminus S$. The dominating set $S$ is a global (strong) offensive alliance if for every vertex $v\in V\setminus S$, the number of neighbors $v$ has in $S$ is at least (greater than) the number of neighbors it has in $V\setminus S$ plus one. The minimum cardinality of a global defensive (strong defensive, offensive, strong offensive) alliance is denoted by $\gamma_a(G)$ ($\gamma_{\hat a}(G)$, $\gamma_o(G)$, $\gamma_{\hat o}(G))$. We compare each of the four parameters $\gamma_a, \gamma_{\hat a}, \gamma_o, \gamma_{\hat o}$ to the independent domination number $i$. We show that $i(G)\le \gamma ^2_a(G)-\gamma_a(G)+1$ and $i(G)\le \gamma_{\hat{a}}^2(G)-2\gamma_{\hat{a}}(G)+2$ for every graph; $i(G)\le \gamma ^2_a(G)/4 +\gamma_a(G)$ and $i(G)\le \gamma_{\hat{a}}^2(G)/4 +\gamma_{\hat{a}}(G)/2$ for every bipartite graph; $i(G)\le 2\gamma_a(G)-1$ and $i(G)=3\gamma_{\hat{a}}(G)/2 -1$ for every tree and describe the extremal graphs; and that $\gamma_o(T)\le 2i(T)-1$ and $i(T)\le \gamma_{\hat o}(T)-1$ for every tree. We use a lemma stating that $\beta(T)+2i(T)\ge n+1$ in every tree $T$ of order $n$ and independence number $\beta(T)$.


Author(s):  
P. Jeyalakshmi ◽  
K. Karuppasamy ◽  
S. Arockiaraj

Let [Formula: see text] be a signed graph. A dominating set [Formula: see text] is said to be an independent dominating set of [Formula: see text] if [Formula: see text] is a fully negative. In this paper, we initiate a study of this parameter. We also establish the bounds and characterization on the independent domination number of a signed graph.


2020 ◽  
Vol 12 (05) ◽  
pp. 2050062
Author(s):  
Murat Erşen Berberler ◽  
Onur Uğurlu ◽  
Zeynep Nihan Berberler

Let [Formula: see text] be a graph. A subset [Formula: see text] of vertices is a dominating set if every vertex in [Formula: see text] is adjacent to at least one vertex of [Formula: see text]. The domination number is the minimum cardinality of a dominating set. Let [Formula: see text]. Then, [Formula: see text] strongly dominates [Formula: see text] and [Formula: see text] weakly dominates [Formula: see text] if (i) [Formula: see text] and (ii) [Formula: see text]. A subset [Formula: see text] of [Formula: see text] is a strong (weak) dominating set of [Formula: see text] if every vertex in [Formula: see text] is strongly (weakly) dominated by at least one vertex in [Formula: see text]. The strong (weak) domination number of [Formula: see text] is the minimum cardinality of a strong (weak) dominating set. A set [Formula: see text] is an independent (or stable) set if no two vertices of [Formula: see text] are adjacent. The independent domination number of [Formula: see text] (independent strong domination number, independent weak domination number, respectively) is the minimum size of an independent dominating set (independent strong dominating set, independent weak dominating set, respectively) of [Formula: see text]. In this paper, mathematical models are developed for the problems of independent domination and independent strong (weak) domination of a graph. Then test problems are solved by the GAMS software, the optima and execution times are implemented. To the best of our knowledge, this is the first mathematical programming formulations for the problems, and computational results show that the proposed models are capable of finding optimal solutions within a reasonable amount of time.


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