Membership for growing context-sensitive grammars is polynomial
Journal of Computer and System Sciences
On measuring nondeterminism in regular languages
Information and Computation
Growing context-sensitive languages and Church-Rosser languages
Information and Computation
Infinite convergent string-rewriting systems and cross-sections for finitely presented monoids
Journal of Symbolic Computation
On monotonic automata with a restart operation
Journal of Automata, Languages and Combinatorics
Church-Rosser Languages vs. UCFL
ICALP '02 Proceedings of the 29th International Colloquium on Automata, Languages and Programming
A grammar based approach to a grammar checking of free word order languages
COLING '94 Proceedings of the 15th conference on Computational linguistics - Volume 2
Measuring nondeterminism in pushdown automata
Journal of Computer and System Sciences
Introduction to Automata Theory, Languages, and Computation (3rd Edition)
Introduction to Automata Theory, Languages, and Computation (3rd Edition)
Modeling syntax of free word-order languages: dependency analysis by reduction
TSD'05 Proceedings of the 8th international conference on Text, Speech and Dialogue
Two-dimensional hierarchies of proper languages of lexicalized FRR-automata
Information and Computation
On lexicalized well-behaved restarting automata that are monotone
DLT'10 Proceedings of the 14th international conference on Developments in language theory
Hi-index | 5.23 |
Restarting automata can be seen as analytical variants of classical automata as well as of regulated rewriting systems. We study a measure for the degree of nondeterminism of (context-free) languages in terms of deterministic restarting automata that are (strongly) lexicalized. This measure is based on the number of occurrences of auxiliary symbols (categories) used for recognizing a language as the projection of its characteristic language onto its input alphabet. This type of recognition is typical for analysis by reduction, a method used in linguistics for the creation and verification of formal descriptions of natural languages. Our main results establish a hierarchy of classes of context-free languages and two hierarchies of classes of non-context-free languages that are based on the expansion factor of a language.