Dieter Kratsch
Metz, France
Minimal Dominating Sets in Graphs: Enumeration,
Combinatorial Bounds and Graph Classes
ABSTRACT:
In 2008 Fomin, Grandoni, Pyatkin and Stepanov provided an exact
exponential time algorithm to enumerate all minimal dominating sets of a
graph. Its main consequence was the first non trivial upper bound on the
number of minimal dominating sets; the maximum number of minimal
dominating sets that a graph on $n$ vertices can have is at most
$1.7159^n$. This upper bound might not be tight, since no examples of
graphs with $1.5705^n$ or more minimal dominating sets are known.
This talk considers exact exponential algorithms to enumerate
minimal dominating sets when the input graphs are restricted to certain
graph classes, among them chordal graphs, cographs and chain graphs.
The following types of results exploiting the structure
of the particular graph classes are presented:
(i) enumeration algorithms based on branching algorithms
and their analysis via upper bounding the number of leaves in
search trees,
(ii) upper bounds on the maximum number of minimal dominating sets
in $n$-vertex graphs obtained via branching algorithms or combinatorial
proofs,
(iii) lower bounds on the maximum number of minimal dominating sets.
In some cases, we provide examples of graphs whose number
of minimal dominating sets exactly matches the proved
upper bound for that class, thereby showing that these bounds are tight.