Fuzzy pushdown automata

Inspired by the similarity of fuzzy regular language to crisp case and the relationship between nondeterministic fuzzy finite automaton and fuzzy regular languages, we study fuzzy pushdown automaton (FPDA) and fuzzy context-free languages (FCFLs). As a generalization, we investigate the movement of one-stack FPDA and discuss the character of multistack FPDA in accepting languages. We get the concept that languages generated by fuzzy context-free K-grammars the languages accepted by one-stack or multistack FPDA are all in the family of FCFL, or say, are usually included in a family of languages generated by Af(K)-fuzzy context-free grammars.