A dominating set of a graph is a subset
of its vertex set
such that every graph vertex
is either in
or adjacent to a graph
vertex in
.
Writing
for the set of these vertices,
this condition is
.
A dominating set of smallest size is called a minimum dominating set and its size is known as the domination number. A dominating set that does not contain any other dominating set as a proper subset is called a minimal dominating set.
For example, in the Petersen graph illustrated above, the set
is a dominating set (and, in fact, a minimum
dominating set).
The domination polynomial encodes the numbers of dominating sets of various sizes.
Other variants of the usual dominating set can be defined, including the so-called total dominating set.
If a set is dominating and irredundant, it is maximal irredundant and minimal dominating (Mynhardt and Roux 2020).
A dominating set is minimal dominating iff it is irredundant (Mynhardt and Roux 2020).
Precomputed dominating sets for many named graphs can be obtained in the Wolfram Language using GraphData[graph, "DominatingSets"].