THE MINIMAL SETS OF AXIOMS CHARACTERIZING ROUGH FUZZY APPROXIMATION OPERATORS

摘要

Axiomatic characterization of rough approximation operators is one of the important aspects in the study of rough set theory. In axiomatic approach, various classes of rough approximation operators are characterized by different sets of axioms. Axioms of approximation operators guarantee the existence of certain types of binary relations producing the same operators. In this paper, the approximation operators determined by a triangular norm are studied, the independence of axioms characterizing rough fuzzy approximation operators is examined, and then the minimal sets of axioms for the characterization of fuzzy approximation operators are presented.