Total Domination Number
The total domination number π gamma_t
of a graph is the size of a smallest total
dominating set, where a total dominating set is a set of vertices of the graph
such that all vertices (including those in the set itself) have a neighbor in the
set. Total dominating numbers are defined only for graphs having no isolated
vertex (plus the trivial case of the singleton
graph π K_1
).
In other words, the total domination number is the size of a minimum
total dominating set.
For example, in the Petersen graph illustrated above, π gamma(P)=3
since the set π S={1,2,9}
is a minimum dominating set (left figure),
while π gamma_t(P)=4
since π S^t={4,8,9,10}
is a minimum total dominating set (right figure).
For any simple graph π G
with no isolated points,
the total domination number π gamma_t
and ordinary domination
number π gamma
satisfy
(Henning and Yeo 2013, p. 17). In addition, if π G
is a bipartite graph, then
(Azarija et al. 2017), where π square
denotes the graph
Cartesian product.
For a connected graph π G
with vertex count π n>=3
,
(Cockayne et al. 1980; Henning and Yeo 2013, p. 11).
See also
Dominating Set, Domination Number, Minimum Total Dominating Set, Total Dominating SetExplore with Wolfram|Alpha
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References
Azarija, J.; Henning, M. A.; and KlavΕΎar, S. "(Total) Domination in Prisms." Electron. J. Combin. 24, No. 1, paper 1.19, 2017. http://www.combinatorics.org/ojs/index.php/eljc/article/view/v24i1p19.Cockayne, E. J., Dawes, R. M., and Hedetniemi, S. T. "Total Domination in Graphs." Networks 10, 211-219, 1980.Henning, M. A. and Yeo, A. Total Domination in Graphs. New York: Springer, 2013.Referenced on Wolfram|Alpha
Total Domination NumberCite this as:
Weisstein, Eric W. "Total Domination Number." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/TotalDominationNumber.html
