Quotients of Context-Free Languages
Journal of the ACM (JACM)
The Unsolvability of the Recognition of Linear Context-Free Languages
Journal of the ACM (JACM)
Journal of the ACM (JACM)
An Infinite Hierarchy of Context-Free Languages
Journal of the ACM (JACM)
Journal of the ACM (JACM)
Closure of families of languages under substitution operators
STOC '70 Proceedings of the second annual ACM symposium on Theory of computing
Intercalation theorems for stack languages
STOC '69 Proceedings of the first annual ACM symposium on Theory of computing
The Mathematical Theory of Context-Free Languages
The Mathematical Theory of Context-Free Languages
Finite automata and their decision problems
IBM Journal of Research and Development
On relations defined by generalized finite automata
IBM Journal of Research and Development
Substitution in families of languages
Information Sciences: an International Journal
Journal of Computer and System Sciences
Checking automata and one-way stack languages
Journal of Computer and System Sciences
Journal of Computer and System Sciences
Proving containment of bounded AFL
Journal of Computer and System Sciences
Journal of Computer and System Sciences
On incomparable abstract family of languages (AFL)
Journal of Computer and System Sciences
Substitution and bounded languages
Journal of Computer and System Sciences
| Hi-index | 0.00 |
The class of syntactic operators is defined. If a full AFL @? is not closed undera syntactic operator @?, then repeated application of @? to @? produces an infinite hierarchy of full AFLs and the closure of @? under @? is not full principal. If @?"1 and @?"2 are incomparable full AFLs, then the least full AFL containing @?"1 and @?"2 is not closed under any syntactic operator. If L is any generator of a full AFL @? closed under any syntactic operator, then all of @? may be expressed as finite state translations of L (without applying concatenation or star). It is shown that substitution, insertion, intercalation and homomorphic replication are all syntactic operators.