Acta Cybernetica
Petri net algorithms in the theory of matrix grammars
Acta Informatica
Syntactic complexity of scattered context grammars
Acta Informatica
Journal of Automata, Languages and Combinatorics
Programmed Grammars and Classes of Formal Languages
Journal of the ACM (JACM)
Generative power of three-dimensional scattered context grammars
Theoretical Computer Science
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
Regulated Rewriting in Formal Language Theory
Regulated Rewriting in Formal Language Theory
Proceedings of the Third International Conference on Machines, Computations, and Universality
MCU '01 Proceedings of the Third International Conference on Machines, Computations, and Universality
Accepting Array Grammars with Control Mechanisms
New Trends in Formal Languages - Control, Cooperation, and Combinatorics (to Jürgen Dassow on the occasion of his 50th birthday)
On the number of nonterminals in linear conjunctive grammars
Theoretical Computer Science
Computational Universality in One-variable Language Equations
Fundamenta Informaticae - SPECIAL ISSUE MCU2004
Refining the nonterminal complexity of graph-controlled, programmed, and matrix grammars
Journal of Automata, Languages and Combinatorics
Workspace theorems for regular-controlled grammars
Theoretical Computer Science
Nonterminal complexity of tree controlled grammars
Theoretical Computer Science
Language classes generated by tree controlled grammars with bounded nonterminal complexity
DCFS'11 Proceedings of the 13th international conference on Descriptional complexity of formal systems
On computational universality in language equations
MCU'04 Proceedings of the 4th international conference on Machines, Computations, and Universality
Language classes generated by tree controlled grammars with bounded nonterminal complexity
Theoretical Computer Science
Computational Universality in One-variable Language Equations
Fundamenta Informaticae - SPECIAL ISSUE MCU2004
Hi-index | 5.23 |
We show that, in the case of context-free programmed grammars with appearance checking working under free derivations, three nonterminals are enough to generate every recursively enumerable language. This improves the previously published bound of eight for the nonterminal complexity of these grammars. This also yields an improved nonterminal complexity bound of four for context-free matrix grammars with appearance checking. Moreover, we establish an upperbound of four on the nonterminal complexity of context-free programmed grammars without appearance checking working under leftmost derivations of type 2. We derive nonterminal complexity bounds for context-free programmed and matrix grammars with appearance checking or with unconditional transfer working under leftmost derivations of types 2 and 3, as well. More specifically, a first nonterminal complexity bound for context-free programmed grammars with unconditional transfer (working under leftmost derivations of type 3) which depends on the size of the terminal alphabet is proved.