Check whether a given set of vertices is a vertex separator.
- The input graph. It may be directed, but edge directions are ignored.
- A numeric vector giving the vertex ids of the candidate separator.
is_separator decides whether the supplied vertex set is a vertex
separator. A vertex set is a vertex separator if its removal results a
In the special case of a fully connected graph with $n$ vertices, each set of $n-1$ vertices is considered to be a vertex separator.
- A logical scalar, whether the supplied vertex set is a (minimal) vertex separator or not.