884 research outputs found
The total bondage number of grid graphs
The total domination number of a graph without isolated vertices is the
minimum number of vertices that dominate all vertices in . The total bondage
number of is the minimum number of edges whose removal enlarges
the total domination number. This paper considers grid graphs. An -grid
graph is defined as the cartesian product of two paths and
. This paper determines the exact values of and
, and establishes some upper bounds of .Comment: 15 pages with 4 figure
The Algorithmic Complexity of Bondage and Reinforcement Problems in bipartite graphs
Let be a graph. A subset is a dominating set if
every vertex not in is adjacent to a vertex in . The domination number
of , denoted by , is the smallest cardinality of a dominating set
of . The bondage number of a nonempty graph is the smallest number of
edges whose removal from results in a graph with domination number larger
than . The reinforcement number of is the smallest number of
edges whose addition to results in a graph with smaller domination number
than . In 2012, Hu and Xu proved that the decision problems for the
bondage, the total bondage, the reinforcement and the total reinforcement
numbers are all NP-hard in general graphs. In this paper, we improve these
results to bipartite graphs.Comment: 13 pages, 4 figures. arXiv admin note: substantial text overlap with
arXiv:1109.1657; and text overlap with arXiv:1204.4010 by other author
Protecting a Graph with Mobile Guards
Mobile guards on the vertices of a graph are used to defend it against
attacks on either its vertices or its edges. Various models for this problem
have been proposed. In this survey we describe a number of these models with
particular attention to the case when the attack sequence is infinitely long
and the guards must induce some particular configuration before each attack,
such as a dominating set or a vertex cover. Results from the literature
concerning the number of guards needed to successfully defend a graph in each
of these problems are surveyed.Comment: 29 pages, two figures, surve
ON THE GRUNDY BONDAGE NUMBERS OF GRAPHS
For a graph , a sequence of distinct vertices of it is called a \emph{dominating sequence} if . The maximum length of dominating sequences is denoted by . We define the Grundy bondage numbers of a graph to be the cardinality of a smallest set of edges for which In this paper the exact values of are determined for several classes of graphs
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