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Showing papers by "Grzegorz Rozenberg published in 1996"


Journal ArticleDOI
TL;DR: This new model of computing, splicing systems, is investigated, and with a few exceptions, the author is able to obtain precise characterizations for all resulting families.

103 citations


Book ChapterDOI
01 Sep 1996

90 citations


Journal ArticleDOI
TL;DR: It is proved that forbidding primitivity in the 2-structures gives a unified approach to some well-known classes of graphs, viz., the cographs and the transitive vertex series-parallel graphs and it is shown that there is a LOGCF algorithm, which recognizes the uniformly nonprimitive 2- structures and constructs their shapes.

30 citations


Journal ArticleDOI
TL;DR: This work considers contextual grammars with parallel derivations, in which the whole current string participates to a derivation step in the sense that it is splitted into substrings to which contexts are adjoined in a parallel manner.
Abstract: Continuing the work begun in [14], we consider contextual grammars (as introduced in [6] with linguistic motivation) with parallel derivations, in which the whole current string participates to a derivation step in the sense that it is splitted into substrings to which contexts are adjoined in a parallel manner. The generative power of such grammars is investigated, when the parallelism is total or partial, and when the selection of contexts is limited to strings in sets of a given type (finite, regular etc.) Then we consider the languages consisting of strings which cannot be further derived (we call them blocking languages). Some open problems are also formulated.

16 citations


Journal ArticleDOI
TL;DR: This paper investigates variants ofsplicing inspired partly by regulating mechanisms customarily studied in language theory, partly by imposing restrictions on the pairs to be spliced or on the result of splicing, and gives new characterizations for families in the Chomsky hierarchy and for closure properties in general.
Abstract: Splicing is a new powerful tool, stemming originally from molecular genetics but investigated extensively also in language theory. In this paper we investigate variants of splicing inspired partly by regulating mechanisms customarily studied in language theory, partly by imposing restrictions on the pairs to be spliced or on the result of splicing. The Chomsky hierarchy constitutes a very suitable test bed for the resulting families, because it is classical and well understood. In contrast to the usual, nonrestricted splicing, we find several cases when the families of regular or of context-free languages are not closed under the new types of splicing. On the other hand, our results give new characterizations for families in the Chomsky hierarchy and for closure properties in general.

11 citations



Journal Article
TL;DR: It is proved that each recursively enumerable language L can be written in the form L — cutd(L' fl R), where L' is a language generated by a one-sided internal contextual grammar witli context-free choice, R is a regular language, and cutd is the operation which removes the prefix bounded by the special symbol d.
Abstract: In this paper we prove that each recursively enumerable language L can be written in the form L — cutd(L' fl R), where L' is a language generated by a one-sided internal contextual grammar witli context-free choice, R is a regular language, and cutd is the operation which removes the prefix bounded by the special symbol d, which appears exactly once in the strings for which cutd is defined. However, the context-free choice sets are always deterministic linear languages of a very simple form. Similar representations can be obtained using one-sided contextual grammars with finite choice and with erased or with erasing contexts. K e y w o r d s . Formal languages, contextual grammars, recursively enumerable languages.

9 citations


Proceedings ArticleDOI
01 May 1996
TL;DR: Towards robustness in parsing - fuzzifying context-free language recognition the computational complexity of PCGS with regular components prefix and periodic languages of rational w-languages Cantor sets and Dejean's conjecture.
Abstract: Towards robustness in parsing - fuzzifying context-free language recognition the computational complexity of PCGS with regular components prefix and periodic languages of rational w-languages Cantor sets and Dejean's conjecture recent developments in trace theory trace language definable with modular quantifiers finite state recognizability for two-dimensional languages - a brief survey on emptiness and counting for alternating finite automata descriptional and computational complexity measure for distributive generation of languages nondeterminism degrees of context-free languages the membership problem for unordered vector languages transforming a single-valued transducer into a mealy machine.

8 citations


Book ChapterDOI
01 Sep 1996

8 citations


Journal ArticleDOI
TL;DR: A characterization of linear languages and a whole landscape of sublinear families is obtained by restricting the contexts to be one-sided (only left-sided or only right-sided) and a characterization of regular languages — here the subregular landscape reduces to two families.
Abstract: The class of external contextual languages isstrictly included in the class of linear languages. A reason for the strict inclusion in linear languages is that external contextual grammars generate languages in the exhaustive way: each sentential form belongs to the language of a grammar. In this paper we study the effect of adding various squeezing mechanisms to the basic classes of exhaustive contextual grammars. We obtain in this way a characterization of linear languages and a whole landscape of sublinear families. By restricting the contexts to be one-sided (only left-sided or only right-sided) we obtain a characterization of regular languages -- here the subregular landscape reduces to two families.

6 citations


Book ChapterDOI
TL;DR: Six classes of generative mechanisms producing languages by starting from a finite set of words and shuffling the current words with words in given sets are considered, with most of the corresponding six families of languages found to be incomparable.
Abstract: We consider generative mechanisms producing languages by starting from a finite set of words and shuffling the current words with words in given sets, depending on certain conditions. Namely, regular and finite sets are given for controlling the shuffling: strings are shuffled only to strings in associated sets. Six classes of such grammars are considered, with the shuffling being done on a leftmost position, on a prefix, arbitrarily, globally, in parallel, or using a maximal selector. Most of the corresponding six families of languages, obtained for finite, respectively for regular selection, are found to be incomparable. The relations of these families with Chomsky language families are briefly investigated.

07 Oct 1996
TL;DR: Several types of matching systems are shown to have the same power as finite automata, one variant is proven to be equivalent to Turing machines, and another one is found to have a strictly intermediate power.
Abstract: We introduce the matching systems, a computability model which is an abstraction of the way of using the Watson-Crick complementarity when computing with DNA in the Adleman style. Several types of matching systems are shown to have the same power as finite automata, one variant is proven to be equivalent to Turing machines, and another one is found to have a strictly intermediate power.

Book
01 Jan 1996
TL;DR: A brief survey on emptiness and counting for alternating finite automata descriptional and computational complexity measure for distributive generation of languages noneterminism degrees of context-free languages is given in this article.
Abstract: Towards robustness in parsing - fuzzifying context-free language recognition the computational complexity of PCGS with regular components prefix and periodic languages of rational w-languages Cantor sets and Dejean's conjecture recent developments in trace theory trace language definable with modular quantifiers finite state recognizability for two-dimensional languages - a brief survey on emptiness and counting for alternating finite automata descriptional and computational complexity measure for distributive generation of languages nondeterminism degrees of context-free languages the membership problem for unordered vector languages transforming a single-valued transducer into a mealy machine.

Journal ArticleDOI
TL;DR: This work introduces a new way of specifying graphs: through languages, i.e., sets of strings, which generalizes the hierarchical specification of particular types of graphs such as cographs and VSP graphs.

02 Jun 1996
TL;DR: This work considers the following new way of generating a language: start with a string w and a given set of insertion contexts (u,v); if uv appears as a substring of w, then the authors can insert in between u and v any subst ring of w which starts with v and ends with u (hence preserving the link restriction encoded by (U,v).
Abstract: We consider the following new way of generating a language: start with a string w and a given set of insertion contexts (u,v); if uv appears as a substring of w, then we can insert in between u and v any substring of w which starts with v and ends with u (hence preserving the link restriction encoded by (u,v)); iterating this operation, we get a language. Many variants can be imagined, concerning the place where the insertion is performed (free, leftmost, etc.), and the string to be inserted (any one, a prefix of the current string, a minimal or a maximal prefix, a minimal or a maximal substring, the whole string, etc.). We investigate here ten such variants, for the case when we have only one insertion context, namely of the form (a,b), where a and b are symbols. The corresponding families of languages are compared to each other (all the relationships are settled), as well as to families in Chomsky hierarchy. A series of topics for further research are pointed out.

Book ChapterDOI
TL;DR: The languages of Parikh prime and of parikh non-prime words are investigated (they are neither semilinear nor slender, hence are not context-free or DOL languages; both of them can be generated by matrix grammars with appearance checking).
Abstract: An n-dimensional vector of natural numbers is said to be prime if the greatest common divisor of its components is one. A word is said to be Parikh prime if its Parikh vector is prime. The languages of Parikh prime and of Parikh non-prime words are investigated (they are neither semilinear nor slender, hence are not context-free or DOL languages; both of them can be generated by matrix grammars with appearance checking).

25 Nov 1996
TL;DR: A modular approach for programming embedded systems with the octopus method and a design notation and toolset for high-performance embedded systems development are presented.
Abstract: Verification of clocked and hybrid systems.- Analyzing and synthesizing hybrid control systems.- Model checking timed automata.- On modeling real-time task systems.- A modular approach for programming embedded systems.- Proof-based system engineering and embedded systems.- A design notation and toolset for high-performance embedded systems development.- The maturity of object-oriented methodologies.- Object oriented development of embedded systems with the octopus method.- Engineering of real-time systems with an experiment in hybrid control.- Formal methods in the design of a storm surge barrier control system.- Statecharts in use: structured analysis and object-orientation.- Embedded systems in consumer products.- The long road from research to telecommunication applications.- Development of embedded software at ICT.

Journal ArticleDOI
TL;DR: Two topics related to binary grammatical codes are presented and it is shown that the only binary codes that are minimal in this sense are the so-called “strict” binary codes (as considered in [3]).