To our families The formal language theory was born in the middle of our century as a tool for modelling and investigating the syntax of natural languages, and it has been developed mainly in connection with programming language handling. Of course, one cannot deny the impulses from neuronal net investigations, from logic, as well as the mathematical motivation of the early researches. The theory has rapidly become a mature one, with specific problems, techniques and results and with an internal self-motivated life. Abstract enough to deal with the essence of modelled phenomena, formal language theory has been applied during the last years to many further non-linguistical fields, sometimes surprisingly far from the previous areas of applications; such fields are developmental biology, economic modelling, semiotics of folklore, dramatic and musical works, cryptography, sociology, psychology, and so on. All these applications as well as the traditional ones to natural and programming languages revealed a rather common conclusion: very frequently, context-free gram mars, the most developed and the most "tractable" type of Chomsky grammars, are not sufficient. "The world is non-context-free" (and we shall "prove" this statement in Section 0.4). On the other hand, the context-sensitive grammars are too powerful and definitely "intractable" (many problems are undecidable or are still open; there is no semantic interpretation of the nonterminals an so on). This is the reason to look for intermediate generative devices, conjoining the simpli city and the beauty of context-free grammars with the power of context-sensitive ones.

No detailed description available for "Regulated Rewriting in Formal Language Theory".

The need for a comprehensive survey-type exposition on formal languages and related mainstream areas of computer science has been evident for some years. In the early 1970s, when the book Formal Languages by the second mentioned editor appeared, it was still quite feasible to write a comprehensive book with that title and include also topics of current research interest. This would not be possible anymore. A standard-sized book on formal languages would either have to stay on a fairly low level or else be specialized and restricted to some narrow sector of the field. The setup becomes drastically different in a collection of contributions, where the best authorities in the world join forces, each of them concentrat ing on their own areas of specialization. The present three-volume Handbook constitutes such a unique collection. In these three volumes we present the current state of the art in formallanguage theory. We were most satisfied with the enthusiastic response given to our request for contributions by specialists representing various subfields. The need for a Handbook of Formal Languages was in many answers expressed in different ways: as an easily accessible his torical reference, a general source of information, an overall course-aid, and a compact collection of material for self-study. We are convinced that the final result will satisfy such various needs.

This textbook gives a systematized and compact summary, providing the most essential types of modern models for languages and computation together with their properties and applications. Most of these models properly reflect and formalize current computational methods, based on parallelism, distribution and cooperation covered in this book. As a result, it allows the user to develop, study, and improve these methods very effectively. This textbook also represents the first systematic treatment of modern language models for computation. It covers all essential theoretical topics concerning them. From a practical viewpoint, it describes various concepts, methods, algorithms, techniques, and software units based upon these models. Based upon them, it describes several applications in biology, linguistics, and computer science. Advanced-level students studying computer science, mathematics, linguistics and biology will find this textbook a valuable resource. Theoreticians, practitioners and researchers working in today’s theory of computation and its applications will also find this book essential as a reference.

This volume provides a selection of the papers which were presented at the eleventh conference on Computational Linguistics in the Netherlands (Tilburg, 2000). It gives an accurate and up-to-date picture of the lively scene of computational linguistics in the Netherlands and Flanders. The volume covers the whole range from theoretical to applied research and development, and is hence of interest to both academia and industry. The target audience consists of students and scholars of computational linguistics, and speech and language processing (Linguistics, Computer Science, Electrical Engineering).

This book constitutes the refereed post-conference proceedings of the 21st International Conference on Membrane Computing, CMC 2020, held as a virtual event, in September 2020. The 10 full papers presented were selected from 31 submissions. The papers deal with all aspects on membrane computing and related areas.