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On differentiation functions, structure functions, and related languages of context-free grammars

Jürgen Dassow, Victor Mitrana, Gheorghe Păun, Ralf Stiebe (2004)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

We introduce the notion of a differentiation function of a context-free grammar which gives the number of terminal words that can be derived in a certain number of steps. A grammar is called narrow (or k -narrow) iff its differentiation function is bounded by a constant (by k ). We present the basic properties of differentiation functions, especially we relate them to structure function of context-free languages and narrow grammars to slender languages. We discuss the decidability of the equivalence...

On differentiation functions, structure functions, and related languages of context-free grammars

Jürgen Dassow, Victor Mitrana, Gheorghe Păun, Ralf Stiebe (2010)

RAIRO - Theoretical Informatics and Applications

We introduce the notion of a differentiation function of a context-free grammar which gives the number of terminal words that can be derived in a certain number of steps. A grammar is called narrow (or k-narrow) iff its differentiation function is bounded by a constant (by k). We present the basic properties of differentiation functions, especially we relate them to structure function of context-free languages and narrow grammars to slender languages. We discuss the decidability of ...

On dot-depth two

F. Blanchet-Sadri (1990)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

On graph products of automatic monoids

A. Veloso Da Costa (2001)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

The graph product is an operator mixing direct and free products. It is already known that free products and direct products of automatic monoids are automatic. The main aim of this paper is to prove that graph products of automatic monoids of finite geometric type are still automatic. A similar result for prefix-automatic monoids is established.

On graph products of automatic monoids

A. Veloso da Costa (2010)

RAIRO - Theoretical Informatics and Applications

The graph product is an operator mixing direct and free products. It is already known that free products and direct products of automatic monoids are automatic. The main aim of this paper is to prove that graph products of automatic monoids of finite geometric type are still automatic. A similar result for prefix-automatic monoids is established.

On hierarchy of the positioned eco-grammar systems

Miroslav Langer (2014)

Kybernetika

Positioned eco-grammar systems (PEG systems, for short) were introduced in our previous papers. In this paper we engage in a new field of research, the hierarchy of PEG systems, namely in the hierarchy of the PEG systems according to the number of agents presented in the environment and according to the number of types of agents in the system.

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