scholarly journals Developmental Systems with Fragmentation

1974 ◽  
Vol 3 (36) ◽  
Author(s):  
Grzegorz Rozenberg ◽  
K. Rouhonen ◽  
Arto Salomaa
Keyword(s):  
Formal Language ◽  
Point Of View ◽  
Formal Language Theory ◽  
Language Theory ◽  
Developmental Systems ◽  
Basic Properties ◽  
New Class ◽  
Theory Point ◽  
L Systems ◽  
Context Free

The paper introduces a new class of L systems, where it is possible to continue derivations from certain specified subwords of the words obtained. Such L systems (called L systems with fragmentation or just JL systems) are of interest both from biological and formal language theory point of view. The paper deals with JL systems without interactions, discusses the basic properties of the language families obtained, as well as their position in the L hierarchy. Finalhy, two infinite hierarchies of language families are obtained by limited fragmentation, the notions being analogous to those of ultralinearity and finiteness of index for context-free languages.

COMPOSITION OF INFLATION RULES FOR APERIODIC STRUCTURES WITH NINE-FOLD SYMMETRY

1999 ◽  
Vol 13 (04) ◽  
pp. 363-373 ◽  
Author(s):  
JUAN GARCÍa ESCUDERO
Keyword(s):  
Finite Number ◽  
Formal Language ◽  
Point Of View ◽  
Formal Language Theory ◽  
Language Theory ◽  
Formal Grammars ◽  
Size And Shape ◽  
Selective Approach ◽  
Theory Point ◽  
Inflation Rules

Deterministic aperiodic planar patterns with nine-fold symmetry have been interpreted recently in terms of a class of formal grammars known as D0L systems. A wider class of patterns with the same symmetry can be generated by composing two inflation rules. They are described with the help of ET0L systems. From the formal language theory point of view this corresponds to a selective approach, due to the fact that we need to introduce nonterminal symbols in the alphabet. From the point of view of quasicrystal structures, instead of having only one pattern of a given size and shape, we now have a finite number of them. This allows to construct nondeterministic models of aperiodic structures.

scholarly journals Derivation "Trees" and Parallelism in Chomsky-Type Grammars

Triangle ◽  
2018 ◽  
pp. 101
Author(s):  
Benedek Nagy
Keyword(s):  
Formal Language ◽  
Phrase Structure ◽  
Formal Language Theory ◽  
Language Theory ◽  
Context Sensitive ◽  
Recursively Enumerable ◽  
Rule Set ◽  
Context Free ◽  
Recursively Enumerable Languages ◽  
Context Free Grammars

In this paper we discuss parallel derivations for context-free, contextsensitive and phrase-structure grammars. For regular and linear grammars only sequential derivation can be applied, but a kind of parallelism is present in linear grammars. We show that nite languages can be generated by a recursion-free rule-set. It is well-known that in context-free grammars the derivation can be in maximal (independent) parallel way. We show that in cases of context-sensitive and recursively enumerable languages the parallel branches of the derivation have some synchronization points. In the case of context-sensitive grammars this synchronization can only be local, but in a derivation of an arbitrary grammar we cannot make this restriction. We present a framework to show how the concept of parallelism can be t to the derivations in formal language theory using tokens.

Formal Grammars and Languages

2012 ◽  
Author(s):  
Carlos Martín-Vide
Keyword(s):  
Systematic Study ◽  
Formal Language ◽  
Formal Language Theory ◽  
Language Theory ◽  
Context Free Grammar ◽  
Formal Grammars ◽  
The Common ◽  
Context Free ◽  
The Way

This article introduces the preliminaries of classical formal language theory. It outlines the main classes of grammars as language-generating devices and automata as language-recognizing devices. It offers a number of definitions and examples and presents the basic results. It classifies grammar according to several criteria. The most widespread one is the form of their productions. This article presents a systematic study of the common properties of language families has led to the theory of abstract families of languages. It shows that a context-free grammar generates not only a set of strings, but a set of trees too: each one of the trees is associated with a string and illustrates the way this string is derived in the grammar.

Computations in Coordinated Pair Systems

1986 ◽  
Vol 9 (4) ◽  
pp. 455-480
Author(s):  
A. Ehrenfeucht ◽  
H.J. Hoogeboom ◽  
G. Rozenberg
Keyword(s):  
General Framework ◽  
Formal Language ◽  
Formal Language Theory ◽  
Language Theory ◽  
Selective Substitution ◽  
Push Down ◽  
Context Free ◽  
Natural Way

Selective substitution grammars provide a rather general framework for the grammatically oriented formal language theory (see, e.g., [R1], [K], and [KR]). They were generalized in [R2] to coordinated table selective substitution systems (ds systems) which provide a convenient unifying framework for both grammars and machines (automata). The present paper investigates coordinated pair (cp) systems which form a subclass of cts systems corresponding in a very natural way to push-down automata: thus cp systems generate context-free languages (all and only). This paper investigates the structure of computations in cp systems.

THE DEVELOPMENT OF FORMAL LANGUAGE THEORY SINCE 1956

1990 ◽  
Vol 01 (04) ◽  
pp. 355-368
Author(s):  
ROBERT McNAUGHTON
Keyword(s):  
Formal Language ◽  
Formal Languages ◽  
Early Years ◽  
Formal Language Theory ◽  
Language Theory ◽  
Personal Interest

This brief survey will discuss the early years of the theory of formal languages through about 1970, treating only the most fundamental of the concepts. The paper will conclude with a brief discussion of a small number of topics, the choice reflecting only the personal interest of the author.

scholarly journals What can formal language theory do for animal cognition studies?

2020 ◽  
Vol 7 (2) ◽  
pp. 191772
Author(s):  
Aniello De Santo ◽  
Jonathan Rawski
Keyword(s):  
Formal Language ◽  
Animal Cognition ◽  
Formal Language Theory ◽  
Language Theory
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