scholarly journals Minimum 2-Tuple Dominating Set of an Interval Graph

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Tarasankar Pramanik ◽  
Sukumar Mondal ◽  
Madhumangal Pal
Keyword(s):  
Positive Integer ◽  
Dominating Set ◽  
Interval Graph ◽  
Interval Graphs ◽  
Point Of View ◽  
Minimum Size ◽  
Domination Problem ◽  
Fixed Positive Integer ◽  
Double Domination

The k-tuple domination problem, for a fixed positive integer k, is to find a minimum size vertex subset such that every vertex in the graph is dominated by at least k vertices in this set. The case when k=2 is called 2-tuple domination problem or double domination problem. In this paper, the 2-tuple domination problem is studied on interval graphs from an algorithmic point of view, which takes O(n2) time, n is the total number of vertices of the interval graph.

An optimal algorithm to find minimum k-hop dominating set of interval graphs

2019 ◽  
Vol 11 (02) ◽  
pp. 1950016 ◽  
Author(s):  
Sambhu Charan Barman ◽  
Madhumangal Pal ◽  
Sukumar Mondal
Keyword(s):  
Positive Integer ◽  
Optimal Algorithm ◽  
Dominating Set ◽  
Interval Graphs ◽  
Fixed Positive Integer

For a fixed positive integer [Formula: see text], a [Formula: see text]-hop dominating set [Formula: see text] of a graph [Formula: see text] is a subset of [Formula: see text] such that every vertex [Formula: see text] is within [Formula: see text]-steps from at least one vertex [Formula: see text], i.e., [Formula: see text]. A [Formula: see text]-hop dominating set [Formula: see text] is said to be minimal if there does not exist any [Formula: see text] such that [Formula: see text] is a [Formula: see text]-hop dominating set of G. A dominating set [Formula: see text] is said to be minimum [Formula: see text]-hop dominating set, if it is minimal as well as it is [Formula: see text]-hop dominating set. In this paper, we present an optimal algorithm to find a minimum [Formula: see text]-hop dominating set of interval graphs with [Formula: see text] vertices which runs in [Formula: see text] time.

An optimal algorithm to find minimum k-hop connected dominating set of permutation graphs

2020 ◽  
pp. 2150049
Author(s):  
Amita Samanta Adhya ◽  
Sukumar Mondal ◽  
Sambhu Charan Barman
Keyword(s):  
Positive Integer ◽  
Optimal Algorithm ◽  
Dominating Set ◽  
Time Algorithm ◽  
Connected Dominating Set ◽  
Permutation Graphs ◽  
Fixed Positive Integer

A set [Formula: see text] is said to be a [Formula: see text]-hop dominating set ([Formula: see text]-HDS) of a graph [Formula: see text] if every vertex [Formula: see text] is within [Formula: see text]-distances from at least one vertex [Formula: see text], i.e. [Formula: see text], where [Formula: see text] is a fixed positive integer. A dominating set [Formula: see text] is said to be minimum [Formula: see text]-hop connected dominating set of a graph [Formula: see text], if it is minimal as well as it is [Formula: see text]-HDS and the subgraph of G made by [Formula: see text] is connected. In this paper, we present an [Formula: see text]-time algorithm for computing a minimum [Formula: see text]-hop connected dominating set of permutation graphs with [Formula: see text] vertices.

A Data Structure on Interval Graphs and Its Applications

1997 ◽  
Vol 07 (03) ◽  
pp. 165-175 ◽  
Author(s):  
Madhumangal Pal ◽  
G. P. Bhattacharjee
Keyword(s):  
Data Structure ◽  
Data Structures ◽  
Interval Graph ◽  
Interval Graphs ◽  
Point Of View ◽  
Interval Tree

In this papar, a new data structure, interval tree (IT), is introduced for an interval graph. Some important properties of IT are studies from the algorithmic point of view. It has many advantages compared to the data structures which are commonly used to solve the problems on interval graphs. Using the properties of IT, the following problems are solved on interval graphs: (i) shortest distances between any two vertices, and (ii) the diameter of the graph.

On Double Domination Numbers of Generalized Petersen Graphs

2016 ◽  
Vol 13 (10) ◽  
pp. 6514-6518
Author(s):  
Minhong Sun ◽  
Zehui Shao
Keyword(s):  
Programming Model ◽  
Dominating Set ◽  
Domination Number ◽  
Upper Bounds ◽  
Minimum Size ◽  
Generalized Petersen Graphs ◽  
Small Parameters ◽  
Petersen Graphs ◽  
Double Domination ◽  
Domination Numbers

A (total) double dominating set in a graph G is a subset S ⊆ V(G) such that each vertex in V(G) is (total) dominated by at least 2 vertices in S. The (total) double domination number of G is the minimum size of a (total) double dominating set of G. We determine the total double domination numbers and give upper bounds for double domination numbers of generalized Petersen graphs. By applying an integer programming model for double domination numbers of a graph, we have determined some exact values of double domination numbers of these generalized Petersen graphs with small parameters. The result shows that the given upper bounds match these exact values.

The strong domination problem in block graphs and proper interval graphs

2019 ◽  
Vol 11 (06) ◽  
pp. 1950063
Author(s):  
Saikat Pal ◽  
D. Pradhan
Keyword(s):  
Maximum Degree ◽  
Dominating Set ◽  
Interval Graphs ◽  
Chordal Graphs ◽  
Minimum Cardinality ◽  
Positive Side ◽  
Degree Of A Vertex ◽  
Block Graphs ◽  
Domination Problem ◽  
Np Complete

In a graph [Formula: see text], the degree of a vertex [Formula: see text], denoted by [Formula: see text], is defined as the number of edges incident on [Formula: see text]. A set [Formula: see text] of vertices of [Formula: see text] is called a strong dominating set if for every [Formula: see text], there exists a vertex [Formula: see text] such that [Formula: see text] and [Formula: see text]. For a given graph [Formula: see text], Min-Strong-DS is the problem of finding a strong dominating set of minimum cardinality. The decision version of Min-Strong-DS is shown to be NP -complete for chordal graphs. In this paper, we present polynomial time algorithms for computing a strong dominating set in block graphs and proper interval graphs, two subclasses of chordal graphs. On the other hand, we show that for a graph [Formula: see text] with [Formula: see text]-vertices, Min-Strong-DS cannot be approximated within a factor of [Formula: see text] for every [Formula: see text], unless NP [Formula: see text] DTIME ([Formula: see text]). We also show that Min-Strong-DS is APX -complete for graphs with maximum degree [Formula: see text]. On the positive side, we show that Min-Strong-DS can be approximated within a factor of [Formula: see text] for graphs with maximum degree [Formula: see text].

A linear time algorithm to compute a minimum restrained dominating set in proper interval graphs

2015 ◽  
Vol 07 (02) ◽  
pp. 1550020 ◽  
Author(s):  
B. S. Panda ◽  
D. Pradhan
Keyword(s):  
Linear Time ◽  
Dominating Set ◽  
Time Algorithm ◽  
Interval Graph ◽  
Chordal Graphs ◽  
Linear Time Algorithm ◽  
Circle Graphs ◽  
Restrained Domination ◽  
Proper Interval Graph ◽  
Domination Problem

A set D ⊆ V is a restrained dominating set of a graph G = (V, E) if every vertex in V\D is adjacent to a vertex in D and a vertex in V\D. Given a graph G and a positive integer k, the restrained domination problem is to check whether G has a restrained dominating set of size at most k. The restrained domination problem is known to be NP-complete even for chordal graphs. In this paper, we propose a linear time algorithm to compute a minimum restrained dominating set of a proper interval graph. We present a polynomial time reduction that proves the NP-completeness of the restrained domination problem for undirected path graphs, chordal bipartite graphs, circle graphs, and planar graphs.

scholarly journals Sortable Simplicial Complexes and $t$-Independence Ideals of Proper Interval Graphs

10.37236/8860 ◽  
2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Jürgen Herzog ◽  
Fahimeh Khosh-Ahang ◽  
Somayeh Moradi ◽  
Masoomeh Rahimbeigi
Keyword(s):  
Positive Integer ◽  
Simplicial Complex ◽  
Simplicial Complexes ◽  
Interval Graph ◽  
Interval Graphs ◽  
Persistence Property ◽  
Proper Interval Graph ◽  
Independence Complex ◽  
Linear Quotients ◽  
The Ideal

We introduce the notion of sortability and $t$-sortability for a simplicial complex and study the graphs for which their independence complexes are either sortable or $t$-sortable. We show that the proper interval graphs are precisely the graphs whose independence complex is sortable. By using this characterization, we show that the ideal generated by all squarefree monomials corresponding to independent sets of vertices of $G$ of size $t$ (for a given positive integer $t$) has the strong persistence property, when $G$ is a proper interval graph. Moreover, all of its powers have linear quotients.

scholarly journals Bipartite graphs with close domination and k-domination numbers

2020 ◽  
Vol 18 (1) ◽  
pp. 873-885
Author(s):  
Gülnaz Boruzanlı Ekinci ◽  
Csilla Bujtás
Keyword(s):  
Positive Integer ◽  
Dominating Set ◽  
Domination Number ◽  
Bipartite Graphs ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Minimum Cardinality ◽  
Vertex Set ◽  
Necessary And Sufficient ◽  
The Given

Abstract Let k be a positive integer and let G be a graph with vertex set V(G) . A subset D\subseteq V(G) is a k -dominating set if every vertex outside D is adjacent to at least k vertices in D . The k -domination number {\gamma }_{k}(G) is the minimum cardinality of a k -dominating set in G . For any graph G , we know that {\gamma }_{k}(G)\ge \gamma (G)+k-2 where \text{Δ}(G)\ge k\ge 2 and this bound is sharp for every k\ge 2 . In this paper, we characterize bipartite graphs satisfying the equality for k\ge 3 and present a necessary and sufficient condition for a bipartite graph to satisfy the equality hereditarily when k=3 . We also prove that the problem of deciding whether a graph satisfies the given equality is NP-hard in general.

k-Efficient domination: Algorithmic perspective

2022 ◽  
Author(s):  
Mohsen Alambardar Meybodi
Keyword(s):  
Decision Problem ◽  
Dominating Set ◽  
Polynomial Time Algorithm ◽  
Time Algorithm ◽  
Chordal Graphs ◽  
Sparse Graphs ◽  
Fpt Algorithm ◽  
Domination Problem ◽  
Efficient Dominating Set ◽  
Np Complete

A set [Formula: see text] of a graph [Formula: see text] is called an efficient dominating set of [Formula: see text] if every vertex [Formula: see text] has exactly one neighbor in [Formula: see text], in other words, the vertex set [Formula: see text] is partitioned to some circles with radius one such that the vertices in [Formula: see text] are the centers of partitions. A generalization of this concept, introduced by Chellali et al. [k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122], is called [Formula: see text]-efficient dominating set that briefly partitions the vertices of graph with different radiuses. It leads to a partition set [Formula: see text] such that each [Formula: see text] consists a center vertex [Formula: see text] and all the vertices in distance [Formula: see text], where [Formula: see text]. In other words, there exist the dominators with various dominating powers. The problem of finding minimum set [Formula: see text] is called the minimum [Formula: see text]-efficient domination problem. Given a positive integer [Formula: see text] and a graph [Formula: see text], the [Formula: see text]-efficient Domination Decision problem is to decide whether [Formula: see text] has a [Formula: see text]-efficient dominating set of cardinality at most [Formula: see text]. The [Formula: see text]-efficient Domination Decision problem is known to be NP-complete even for bipartite graphs [M. Chellali, T. W. Haynes and S. Hedetniemi, k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122]. Clearly, every graph has a [Formula: see text]-efficient dominating set but it is not correct for efficient dominating set. In this paper, we study the following: [Formula: see text]-efficient domination problem set is NP-complete even in chordal graphs. A polynomial-time algorithm for [Formula: see text]-efficient domination in trees. [Formula: see text]-efficient domination on sparse graphs from the parametrized complexity perspective. In particular, we show that it is [Formula: see text]-hard on d-degenerate graphs while the original dominating set has Fixed Parameter Tractable (FPT) algorithm on d-degenerate graphs. [Formula: see text]-efficient domination on nowhere-dense graphs is FPT.

A note on improved upper bounds on the transversal number of hypergraphs

2019 ◽  
Vol 11 (01) ◽  
pp. 1950004
Author(s):  
Michael A. Henning ◽  
Nader Jafari Rad
Keyword(s):  
Upper Bound ◽  
Dominating Set ◽  
Domination Number ◽  
Minimum Size ◽  
Total Domination ◽  
Total Domination Number ◽  
Minimum Cardinality ◽  
Total Dominating Set ◽  
Isolated Vertex ◽  
Transversal Number

A subset [Formula: see text] of vertices in a hypergraph [Formula: see text] is a transversal if [Formula: see text] has a nonempty intersection with every edge of [Formula: see text]. The transversal number of [Formula: see text] is the minimum size of a transversal in [Formula: see text]. A subset [Formula: see text] of vertices in a graph [Formula: see text] with no isolated vertex, is a total dominating set if every vertex of [Formula: see text] is adjacent to a vertex of [Formula: see text]. The minimum cardinality of a total dominating set in [Formula: see text] is the total domination number of [Formula: see text]. In this paper, we obtain a new (improved) probabilistic upper bound for the transversal number of a hypergraph, and a new (improved) probabilistic upper bound for the total domination number of a graph.

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