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.

Graph Surfing by Reaction Systems

Abstract: In this paper, we introduce graph-based reaction systems as a generalization of set-based reaction systems, a novel and well-investigated model of interactive computation. Graph-based reaction systems allow us to introduce a novel methodology for graph transformation, which is not based on the traditional “cut, add, and paste” approach, but rather on moving within a “universe” graph B (surfing on B) from a subgraph of B to a subgraph of B, creating subgraph trajectories within B. We illustrate this approach by small case studies: simulating finite state automata, implementing a shortest paths algorithm, and simulating cellular automata.

Simple operations for gene assembly

Abstract: The intramolecular model for gene assembly in ciliates considers three operations, Id, hi, and diad that can assemble any gene pattern through folding and recombination: the molecule is folded so that two occurrences of a pointer (short nucleotide sequence) get aligned and then the sequence is rearranged through recombination of pointers. In general, the sequence rearranged by one operation can be arbitrarily long and consist of many coding and non-coding blocks. We consider in this paper some simpler variants of the three operations, where only one coding block is rearranged at a time. We characterize in this paper the gene patterns that can be assembled through these variants. Our characterization is in terms of signed permutations and dependency graphs. Interestingly, we show that simple assemblies possess rather involved properties: a gene pattern may have both successful and unsuccessful assemblies and also more than one successful assembling strategy.

A note on universal grammars

Abstract: In this note we present an elementary proof of the following result due to T. Kasai: for each alphabet Σ there exists a context free grammar G such that for each context-free language K over Σ a regular control set C can be found such that G controlled by C and operating in the leftmost fashion generates K. We prove an analogous result for type-O grammars and the family of recursively enumerable languages.

Developmental Systems with Fragmentation

Abstract: 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.

Petri nets: Properties, analysis and applications

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. >