Jrgen Dassow

Bio: Jrgen Dassow is an academic researcher. The author has contributed to research in topics: Context-sensitive grammar & Tree-adjoining grammar. The author has an hindex of 1, co-authored 1 publications receiving 838 citations.

Regulated rewriting in formal language theory

Abstract: It is well-known that context-free grammars cannot cover all aspects of natural languages, progamming languages and other related fields. Therefore a lot of mechanisms have been introduced which control the application of context-free rules. This book presents 25 different regulating mechanisms by definitions, examples and basic facts, especially concerning hierarchies. Matrix, programmed, and random context grammars as typical representants are studied in more detail. Besides their algebraic and decidability properties a comparison is made with respect to syntactic complexity measures and pure versions. Further topics are combinations of some control mechanisms, regulated L systems, automata characterizations, Szilard languages, and grammar forms of regulated grammars as well as selective substitution grammars as one common generalization.

Tissue P systems

Abstract: Starting from the way the inter-cellular communication takes place by means of protein channels (and also from the standard knowledge about neuron functioning), we propose a computing model called a tissue P system, which processes symbols in a multiset rewriting sense, in a net of cells. Each cell has a finite state memory, processes multisets of symbol-impulses, and can send impulses (“excitations”) to the neighboring cells. Such cell nets are shown to be rather powerful: they can simulate a Turing machine even when using a small number of cells, each of them having a small number of states. Moreover, in the case when each cell works in the maximal manner and it can excite all the cells to which it can send impulses, then one can easily solve the Hamiltonian Path Problem in linear time. A new characterization of the Parikh images of ET0L languages is also obtained in this framework. Besides such basic results, the paper provides a series of suggestions for further research.

Grammar Systems: A Grammatical Approach to Distribution and Cooperation

Abstract: From the Publisher: This book investigates two major systems: firstly, cooperating distributed grammar systems, where the grammars work on one common sequential form and the cooperation is realized by the control of the sequence of active grammars; secondly, parallel communicating grammar systems, where each grammar works on its own sequential form and cooperation is done by means of communicating between grammars. The investigation concerns hierarchies with respect to different variants of cooperation, relations with classical formal language theory, syntactic parameters such as the number of components and their size, power of synchronization, and general notions generated from artificial intelligence.

The power of communication: P systems with symport/antiport

Abstract: In the attempt to have a framework where the computation is done by communication only, we consider the biological phenomenon of trans-membrane transport of couples of chemicals (one say symport when two chemicals pass together through a membrane, in the same direction, and antiport when two chemicals pass simultaneously through a membrane, in opposite directions). Surprisingly enough, membrane systems without changing (evolving) the used objects and with the communication based on rules of this type are computationally complete, and this result is achieved even for pairs of communicated objects (as encountered in biology). Five membranes are used; the number of membranes is reduced to two if more than two chemicals may collaborate when passing through membranes.