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.

Computational processes in living cells: gene assembly in ciliates

Abstract: One of the most complex DNA processing in nature known to us is carried out by ciliates during the sexual reproduction when their micronuclear genome is transformed to the macronuclear genome. This process of gene assembly is intriguing and captivating also from the computational point of view.We investigate here three intramolecular molecular operations (ld, hi, and dlad) postulated to accomplish gene assembly. The formal models for these operations are formulated on three different abstraction levels: MDS descriptors, legals strings and overlap graphs. In general both legal strings and overlap graphs contain strings and graphs that do not model any micronuclear gene. After a short survey of gene assembly we study the problem of recognizing whether a general legal string or a general overlap graph is a formalization of a micronuclear gene.

Towards a petri net semantics for membrane systems

Abstract: We consider the modelling of the behaviour of membrane systems using Petri nets. First, a systematic, structural link is established between a basic class of membrane systems and Petri nets. To capture the compartmentisation of membrane systems, localities are proposed as an extension of Petri nets. This leads to a locally maximal concurrency semantics for Petri nets. We indicate how processes for these nets could be defined which should be of use in order to describe what is actually going on during a computation of a membrane system.

Transition Systems, Event Structures and Unfoldings

Abstract: Elementary transition systems were introduced by the authors in DAIMI PB-310. They were proved to be, in a strong categorical sense, the transition system version of elementray net systems. The question arises whether the notion of a region and the axioms (mostly based on regions) imposed on ordinary transition systems to obtain elementray net systems. Stated differently, one colud ask whether elementray transition systems could also play a role in characterizing other models of concurrency. We show here that by smoothly stengthening the axioms of elementary transition systems one obtains a subclass called occurrence transitions systems which turn out to be categorically equivalent to the well-known model of concurrency called prime event structures. Next we show that occurrence transition systems are to elementry transition systems what occurrence nets are to elementary nets systems. We define an ''unfold'' operation on elementry transition systems which yields occurrence transistion systems. We then prove that this operation uniquely extends to a functor which is the right adjoint to the inclusion functor from (the full subcategory of) occurrence transition systems to (the category of) elementary transition systems. Thus the results of this paper also show that the semantic theory of elementray net systems has a nice counterpart in the more abstract world of transition systems.

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. >