Comparing Imperfection Ratio and Imperfection Index for Graph Classes
Perfect graphs constitute a well-studied graph class with a rich structure, reflected by many characterizations with respect to different concepts. Perfect graphs are, for instance, precisely those graphs where the stable set polytope STAB() coincides with the fractional stable set polytope QSTAB(). For all imperfect graphs it holds that STAB() ⊂ QSTAB(). It is, therefore, natural to use the difference between the two polytopes in order to decide how far an imperfect graph is away from...