Journal ArticleDOI
The Sequence Equivalence Problem is Decidable for 0S Systems
TLDR
It is shown that it is decidable whether or not two arbitrary 0S systems generate the same set of (derivation) sequences, and it is obtained as a corollary that two arbitrary context-free grammars have the same sets of derivation sequences.Abstract:
0S systems generalize context-free grammars without nontermmals it is shown that it is decidable whether or not two arbitrary 0S systems generate the same set of (derivation) sequences It is obtained as a corollary that it is decidable whether or not two arbitrary context-free grammars have the same sets of derivation sequencesread more
Citations
More filters
Journal ArticleDOI
A characterization of context-free string languages by directed node-label controlled graph grammars
Dirk Janssens,Grzegorz Rozenberg +1 more
TL;DR: This work provides a characterization of the class of context-free string languages in terms of DNLC grammars, and studies the use of those Grammars to define string languages.
Journal ArticleDOI
Grammatical codes of trees
TL;DR: It is shown that there are exactly 120 insertive strict codes, which are codes of a grammatical nature and a characterization of these codes (and their various subclasses) is given in grammatical terms.
References
More filters
Book
Developmental systems and languages
TL;DR: Developmental systems were introduced in order to model morphogenetic (pattern-generating) processes in growing, multicellular, filamentous organisms by considering the states and outputs to be identical and thus omitting the output functions.
Journal ArticleDOI
On sentential forms of context-free grammars
TL;DR: SF-languages, i.e., languages which equal the set of sentential forms of a context-free grammar, possess some of the properties of context- free languages but their family is not closed under any of the ordinary operations.