Back Gramàtica sense restriccions Catalan Gramatika neograničenih produkcija Croatian Gramatyka kombinatoryczna Polish Gramática irrestrita Portuguese Неограниченная грамматика Russian Граматика без ограничења Serbian 无限制文法 Chinese
In automata theory, the class of unrestricted grammars (also called semi-Thue, type-0 or phrase structure grammars) is the most general class of grammars in the Chomsky hierarchy. No restrictions are made on the productions of an unrestricted grammar, other than each of their left-hand sides being non-empty.[1]: 220 This grammar class can generate arbitrary recursively enumerable languages.