A Note on Cycle Grammars

Grammars whose languages consist of cycles (“necklaces”) rather than strings are considered. If G is context free, and we regard G as generating cycles instead of strings, the resulting language is just what we would get if we “bent” the strings of L ( G ) into cycles. This is no longer true if G is context sensitive. However, in this case too, the context-sensitive cycle languages are just the “bendings” of the context-sensitive string languages. Automata on cyclic tapes are also discussed.