Extending kernel perfect digraphs to kernel perfect critical digraphs (Q1182966)

An independent subset \(K\) of the vertex set of a digraph \(D\) is said to be a kernel of \(D\) if every vertex which does not belong to \(K\) has a successor in \(K\). The authors have proved that any kernel perfect digraph (every induced subdigraph has a kernel) can be extended to a kernel perefect critical digraph (with no kernels, but the deletion of any vertex produces a digraph with a kernel).