A hyper-AFL is an abstract family of languages which is closed under iterated (parallel) substitution. In this paper we establish the existence of infinite chains of full hyper-AFL's strictly in between the context-free and context-sensitive languages. Several useful auxiliary results concerning derivation-controlled parallel rewriting systems are developwd in the proof.
|Place of Publication||Enschede|
|Publisher||University of Twente, Department of Applied Mathematics|
|Number of pages||23|
|Publication status||Published - 1975|
- HMI-SLT: Speech and Language Technology