SOLUTION:
A subset
such that the subgraph induced by V-V' is
connected and has the property P.
MEASURE:
Cardinality of the set of deleted vertices, i.e., .
Bad News:
Not approximable within
for any
if P
is any non-trivial hereditary property determined by the blocks (for example
planar, outerplanar, bipartite, chordal, cactus, acyclic graph, acyclic
digraph, without cycles of specified length, symmetric digraph,
antisymmetric digraph)
[470].