Conditional Context-Free Languages of Finite Index
نویسندگان
چکیده
We consider conditional context-free grammars that generate languages of nite index. Thereby, we solve an open problem stated in Dassow and PP aun's monograph on regulated rewriting. Moreover, we show that conditional context-free languages with context-free conditions of nite index are more powerful than conditional context-free languages with regular conditions of nite index. Furthermore, we study the complexity of membership and non-emptiness for conditional and programmed languages respectively grammars (of nite index) with regular, linear, and context-free core rules and conditions.
منابع مشابه
Regulated Finite Index Language Families Collapse
We prove normal form theorems for programmed, ordered, and random context, context-free grammars as well as context-free grammars with regular context conditions of nite index. Based on these normal forms, we reprove that the family of programmed, ordered , permitting, and forbidding random context context-free languages of nite index coincide, regardless whether erasing productions, i.e., rule...
متن کاملConditional Lindenmayer Systems with Subregular Conditions: The Extended Case
We study the generative power of extended conditional Lindenmayer systems where the conditions are finite, monoidal, combinational, definite, nilpotent, strictly locally (k)-testable, commutative, circular, suffix-closed, starfree, and union-free regular languages. The results correspond to those obtained for conditional context-free languages.
متن کاملSome further remarks on the family of finite index matrix languages
— Itis proved that thefamily of finite index matrix languages coincides with the families of finite index random context languages generated withforbidding sets and with or without X-rules and is included in thefamily of finite index conditional languages. Finally, the Szilard languages associated to finite index matrix grammars are briefly investigated. Résumé. — On montre que lafamille de lan...
متن کاملGroups with Context-free Co-word Problem
The class of co-context-free groups is studied. A co-context-free group is defined as one whose coword problem (the complement of its word problem) is context-free. This class is larger than the subclass of context-free groups, being closed under the taking of finite direct products, restricted standard wreath products with context-free top groups, and passing to finitely generated subgroups an...
متن کاملFinite State Temporality and Context-Free Languages
In the finite-state temporality approach, events in natural language semantics have been characterized in regular languages, with strings representing sequences of temporal observations. We extend this approach to natural language constructions which are not regular. Context-free constructions are detailed and discussed. Superposition, the key operator in the finite-state temporality approach i...
متن کامل