Many-level fuzzy rough approximation spaces induced by many-level fuzzy preorders and the related ditopological structures
Alexander Šostak, Ingrīda Uļjane, Aleksandrs Eļkins · 2019
We present a many-level version for the Pawlak -Dubois&Prade theory of rough approximation of fuzzy sets.Basing on the many-level upper and lower fuzzy rough approximation operators, we define the measure of rough approximation that in a certain sense characterizes the quality of the obtained approximation.Further, the fuzzy rough approximation operators give rise to two alternative topological-type structures considered in the paper.