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Grzegorz Rozenberg

Bio: Grzegorz Rozenberg is an academic researcher from Leiden University. The author has contributed to research in topics: Petri net & Formal language. The author has an hindex of 81, co-authored 679 publications receiving 31378 citations. Previous affiliations of Grzegorz Rozenberg include Åbo Akademi University & University of Warsaw.


Papers
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Journal ArticleDOI
TL;DR: The main theorem is a result on the combinatorial structure of graph languages generated by NLC grammars; it resembles the pumping theorem for context-free string languages.

163 citations

Journal ArticleDOI
TL;DR: The boundary NLC (BNLC) grammars as discussed by the authors are a generalization of node label controlled (NLC) graphs, which define languages of undirected node labeled graphs (or, if we just omit the labels, languages of unlabeled graphs).
Abstract: Node label controlled (NLC) grammars are graph grammars (operating on node labeled undirected graphs) which rewrite single nodes only and establish connections between the embedded graph and the neighbors of the rewritten node on the basis of the labels of the involved nodes only. They define (possibly infinite) languages of undirected node labeled graphs (or, if we just omit the labels, languages of unlabeled graphs). Here we consider a restriction of NLC grammars, so-called boundary NLC (BNLC) grammars , distinguished by the property that whenever in a graph already generated two nodes may be rewritten, then these nodes are not adjacent. The graph languages generated by this type of grammars are called BNLC languages . Although we show that this restriction leads to a smaller class of languages, still enough generative power remains to define interesting graph languages. For example, trees, complete bipartite graphs, maximal outerplanar graphs, k -trees, graphs of bandwidth ⩽ k , graphs of cyclic bandwidth ⩽ k , graphs of binary tree bandwidth ⩽ k , graphs of cutwidth ⩽ k (always for a fixed positive integer k ) turn out all to be BNLC languages. We prove a number of normal forms for BNLC grammars and then we indicate their usefulness by various applications. In particular, we show that for connected graphs of bounded degree the membership problem for BNLC languages is solvable in deterministic polynomial time.

151 citations

Journal ArticleDOI
TL;DR: A new method of computing using DNA plasmids is introduced, applicable to a wide variety of algorithmic problems, and the potential advantages are listed.
Abstract: A new method of computing using DNA plasmids is introduced and the potential advantages are listed. The new method is illustrated by reporting a laboratory computation of an instance of the NP-complete algorithmic problem of computing the cardinal number of a maximal independent subset of the vertex set of a graph. A circular DNA plasmid, specifically designed for this method of molecular computing, was constructed. This computational plasmid contains a specially inserted series of DNA sequence segments, each of which is bordered by a characteristic pair of restriction enzyme sites. For the computation reported here, the DNA sequence segments of this series were used to represent the vertices of the graph being investigated. By applying a scheme of enzymatic treatments to the computational plasmids, modified plasmids were generated from which the solution of the computational problem was selected. This new method of computing is applicable to a wide variety of algorithmic problems. Further computations in this style are in progress.

148 citations

Journal ArticleDOI
TL;DR: A number of ways to assign (code) sets of numbers to (by) spike trains are considered, and it is proved then computational completeness: the computed sets of Numbers are exactly Turing computable sets.
Abstract: We continue here the study of the recently introduced spiking neural P systems, which mimic the way that neurons communicate with each other by means of short electrical impulses, identical in shape (voltage), but emitted at precise moments of time. The sequence of moments when a neuron emits a spike is called the spike train (of this neuron); by designating one neuron as the output neuron of a spiking neural P system II, one obtains a spike train of II. Given a specific way of assigning sets of numbers to spike trains of II, we obtain sets of numbers computed by II. In this way, spiking neural P systems become number computing devices. We consider a number of ways to assign (code) sets of numbers to (by) spike trains, and prove then computational completeness: the computed sets of numbers are exactly Turing computable sets. When the number of spikes present in the system is bounded, a characterization of semilinear sets of numbers is obtained. A number of research problems is also formulated.

148 citations


Cited by
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Journal ArticleDOI
01 Apr 1989
TL;DR: The author proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis, and one section is devoted to marked graphs, the concurrent system model most amenable to analysis.
Abstract: Starts with a brief review of the history and the application areas considered in the literature. The author then proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis. In particular, one section is devoted to marked graphs, the concurrent system model most amenable to analysis. Introductory discussions on stochastic nets with their application to performance modeling, and on high-level nets with their application to logic programming, are provided. Also included are recent results on reachability criteria. Suggestions are provided for further reading on many subject areas of Petri nets. >

10,755 citations

Journal ArticleDOI
TL;DR: Alur et al. as discussed by the authors proposed timed automata to model the behavior of real-time systems over time, and showed that the universality problem and the language inclusion problem are solvable only for the deterministic automata: both problems are undecidable (II i-hard) in the non-deterministic case and PSPACE-complete in deterministic case.

7,096 citations