Place-Labeled Petri Net Controlled Grammars

A place-labeled Petri net (pPN) controlled grammar is a context-free grammar equipped with a Petri net and a function which maps places of the net to the productions of the grammar. The language consists of all terminal strings that can be obtained by simultaneously applying of the rules of multisets which are the images of the sets of the input places of transitions in a successful occurrence sequence of the Petri net. In this paper, we study the generative power and structural properties of pPN controlled grammars. We show that pPN controlled grammars have the same generative power as matrix grammars. Moreover, we prove that for each pPN controlled grammar, we can construct an equivalent place-labeled ordinary net controlled grammar

State machine of place-labelled Petri net controlled grammars

A place-labelled Petri net controlled grammar is, in general, a context-free grammar equipped with a Petri net and a function which maps places of the net to productions of the grammar. The languages of place-labelled Petri net controlled grammar consist of all terminal strings that can be obtained by parallel application of the rules of multisets which are the images of the sets of input places in a successful occurrence sequence of the Petri net. In this paper, we investigate the structural subclass of place-labelled Petri net controlled grammar which focus on the state machine. We also establish the generative capacity of state machine of place-labelled Petri net controlled grammars

Watson-crick petri net and place-labelled petri net controlled grammar using formal language theory

formal language theory is a branch of applied discrete mathematics and theoretical computer science. a watson-crick automaton is an automaton that works on tapes which are double-stranded sequences of symbols related by watson-crick complementarity that are similar to the dna molecules. a petri net is a model of information flow in systems that provides a useful mathematical formalism for modelling concurrent systems. in this thesis, the relation between watson-crick automata and petri nets is investigated to consider the massive parallelism in watson- crick automata. thus, a new concept called watson-crick petri net is introduced. besides that, the structural properties of watson-crick petri net are found, namely a single start place, a run place and the stop transition. also, the generative power of watson-crick petri net is determined. besides using watson-crick complementarity in petri nets, a context-free grammar is also considered in this research. a petri net controlled grammar is a type of a context-free grammar equipped with petri nets, where the successful derivation of the grammar can be simulated by the sequence of occurrences of the net. the production rules of a grammar, for all variants of petri net controlled grammars that have been introduced, are associated only with transitions of a petri net. therefore, a place-labelled petri net controlled grammar is introduced in this research. the place labelling enables the parallel application of production rules in petri net controlled grammars to be considered. the effects of labelling strategies and the set of final markings, along with lower and upper bounds are chosen in order to increase the generative power of place-labelled petri net controlled grammar. besides that, the structural properties and structural subclass of place-labelled petri net controlled grammar are also found in this thesis

Petri net controlled grammars

Different types of regulated grammars have been introduced in order to supplement shortcomings of context-free grammars in applications preserving their elegant mathematical properties. However, the rapid developments in present day industry, biology, and other areas challenge to deal with various tasks which need suitable tools for their modelling and investigation. We propose Petri net controlled grammars as models for representing and analyzing of metabolic pathways in living cells where Petri nets are responsible for the structure and communication of the pathways, and grammars represent biochemical processes. On the other hand, the control by Petri nets has also theoretical interest: it extends possibilities to introduce and investigate concurrent control mechanisms in formal language theory. The thesis introduces various variants of Petri net controlled grammars using different types of Petri nets and investigates their mathematical properties such as computational power and closure properties.Los diferentes tipos de gramáticas con reescritura regulada han sido introducidas para complementar las deficiencias de las gramáticas libres del contexto en las aplicaciones, preservando sus propiedades matemáticas. Por otro lado, la rápida evolución la biología, y otras áreas actuales supone un reto para tratar de las tareas varias que necesitan las herramientas adecuadas para la elaboración de modelos e investigación. Proponemos gramáticas controladas por redes de Petri como modelos para representar y analizar los procesos bioquímicos en las células vivas donde redes de Petri son responsables de la estructura, y gramáticas representan los procesos generativos. Además, el control de redes de Petri también tiene interés teórico: amplía las posibilidades de investigar los mecanismos de control concurrente en la teoría de lenguajes formales. La tesis presenta distintas variantes de gramáticas controladas por redes de Petri e investiga sus propiedades matemáticas

On Erasing Rules in Regulated Grammars

V této práci je diskutován vliv vymazávacích pravidel na generativní sílu řízených gramatik, což je velký otevřený problém teorie řízeného přepisování. Tato práce studuje možnost odstranění vymazávacích pravidel z těchto gramatik tak, že shromažďuje aktuální výsledky na toto téma a přináší novou podmínku, nazvanou k-limitované vymazávání, která zaručuje, že jsme bez vlivu na generovaný jazyk schopni odstranit všechna vymazávací pravidla z libovolné bezkontextové gramatiky řízené regulárním jazykem splňující tuto podmínku. Tento výsledek je částečným řešením výše zmíněného problému. Mimoto je prezentován nový algoritmus k odstranění vymazávacích pravidel z bezkontextových gramatik, který nepotřebuje předurčovat tzv. epsilon-neterminály (na rozdíl od standardního algoritmu používaného v učebnicích). V závěru je zhodnocen přínos těchto výsledků pro syntaktickou analýzu.This work discusses the effect of erasing rules to the generative power of regulated grammars, which is a big open problem in the theory of regulated rewriting. It studies the possibility of removal of erasing rules from regulated grammars by aggregation of current, up-to-date results concerning this elimination and by presentation of a new condition, called k-limited erasing, under which all erasing rules can be always removed from regularly controlled context-free grammars without affecting their generative power. This result partially solves the abovementioned problem. Moreover, a new algorithm for elimination of erasing rules from context-free grammars is presented. This algorithm does not require any predetermination of so called epsilon-nonterminals (in contrast to the standard algorithm used in textbooks). In the conclusion, a significance of these results concerning syntactical analysis is discussed.