On permutative grammars generating context-free languages
A grammar is said to be permutative if it has permutation productions of the form AB\(\to BA\) in addition to context-free productions. Szilard languages and label languages are studied as examples of languages generable by permutative grammars. Particularly, sufficient conditions for a permutative grammar to generate a context-free language are studied.
scientific article; zbMATH DE number 3932415