Pumping lemma in context-free grammar theory based on complete residuated lattice-valued logic

Residuated lattices are important algebras and have close links with various important algebras. Automata theory based on complete residuated lattice-valued logic, called L -valued automata, has been established by the second author in 2001 and 2002. As a continuation of automata theory based on complete residuated lattice-valued logic, in this paper, we mainly deal with the problem concerning pumping lemma in L -valued context-free languages ( L -CFLs). As a generalization of the notion in the theory of formal grammars, the definition of L -valued context-free grammars ( L -CFGs) is introduced. We also discuss a special case of L -CFGs, L -right (or left)-linear grammars, and show the equivalence between L -linear grammars and L -regular grammars. This result shows that we generalize the pumping lemma in L -valued regular languages ( L -RLs) more recently established by the second author.