Abstract:

Instead of the classical definition of rough sets based on an indiscernibility relation, an alternative approach is suggested, based on a relation which quantifies the effort and other demands necessary to decide the membership predicate for a given element and a given set. The points for which this effort exceeds a threshold value are taken as undecidable. A simply defined inverse mapping of this quantifying relation may be taken as a membership degree function which defines fuzzy sets in the universe of discourse.