On relationships among fuzzy approximation operators, fuzzy topology, and fuzzy automata.
\textit{P. Das} [Fuzzy Sets Syst. 105, 469--479 (1999; Zbl 0959.68071)] introduced a fuzzy topology on a state-set of a fuzzy finite state machine and showed that fuzzy systems (in the sense of Malik and Mordeson) are precisely the closed fuzzy sets in this fuzzy topology. In the given paper the authors introduce a different fuzzy topology on the state-set of a fuzzy automaton (a concept which is a slight modification of a fuzzy finite state machine) and show that closed fuzzy sets in this fuzzy topology are precisely the strong fuzzy systems. In their work the authors essentially use the so called ``approximation operators'' on an ``approximation space'' -- concepts which are also used in the study of rough sets.
scientific article; zbMATH DE number 1975918