Cooperating Distributed Grammar Systems of Finite Index Working in Hybrid Modes

We study cooperating distributed grammar systems working in hybrid modes in connection with the finite index restriction in two different ways: firstly, we investigate cooperating distributed grammar systems working in hybrid modes which characterize programmed grammars with the finite index restriction; looking at the number of components of such systems, we obtain surprisingly rich lattice structures for the inclusion relations between the corresponding language families. Secondly, we impose the finite index restriction on cooperating distributed grammar systems working in hybrid modes themselves, which leads us to new characterizations of programmed grammars of finite index.Comment: In Proceedings AFL 2014, arXiv:1405.527

Array P Systems and t−Communication

The two areas of grammar systems and P systems, which have provided interesting computational models in the study of formal string language theory have been in the recent past effectively linked in [4] by incorporating into P systems, a communication mode called t−mode of cooperating distributed grammar systems. On the other hand cooperating array grammar systems [5]and array P systems [1] have been developed in the context of two-dimensional picture description. In this paper, motivated by the study of [4], these two systems are studied by linking them through the t−communication mode, thus bringing out the picture description power of these systems

Structuring grammar systems by priorities and hierarchies

A grammar system is a finite set of grammars that cooperate to generate a language. We consider two generalizations of grammar systems: (l) adding a priority relation between single grammar components, and (2) considering hierarchical components which by themselves are grammar systems. The generative power of these generalized grammar systems is investigated, and compared with the generative power of ordinary grammar systems and of some well-known types of grammars with regulated rewriting (such as matrix grammars). We prove that for many cooperating strategies the use of priority relation increases the generative capacity, however this is not the case for the maximal mode of derivation (an important case, because it gives a characterization of the ETOL languages). We also demonstrate that in many cases the use of hierarchical components does not increase the generative power

Grammar Systems and Parsing Based on Them

Tato práce se věnuje problematice gramatických systémů. Definuje jak kooperující distribuované CD gramatické systémy, tak i paralelně komunikující PC gramatické systémy ve spojení s bezkontextovými gramatikami. Dále zkoumá jejich principy a generativní síly v různých režimech a vůči různým jazykům. Studuje využití gramatických systémů při syntaktické analýze. Zaměřuje se především na spojení syntaktické analýzy shora dolů s precedenční analýzou zdola nahoru ve spojitosti s PC gramatickými systémy.This work is devoted to grammar systems. Defines cooperating distributed grammar systems CD and parallel communicating grammar systems PC in conjunction with context-free grammars. It also examines their principles and generative forces in different regime and to different languages. Studying the use of grammatical parsing systems. It focuses primarily on top-down parsing and precedential bottom-up analysis in conjunction with the PC grammar systems.

Cooperating distributed grammar systems with random context grammars as components

In this paper, we discuss cooperating distributed grammar systems where components are (variants of) random context grammars. We give an overview of known results and open problems, and prove some further results

Natural Language Dialogue Service for Appointment Scheduling Agents

Appointment scheduling is a problem faced daily by many individuals and organizations. Cooperating agent systems have been developed to partially automate this task. In order to extend the circle of participants as far as possible we advocate the use of natural language transmitted by e-mail. We describe COSMA, a fully implemented German language server for existing appointment scheduling agent systems. COSMA can cope with multiple dialogues in parallel, and accounts for differences in dialogue behaviour between human and machine agents. NL coverage of the sublanguage is achieved through both corpus-based grammar development and the use of message extraction techniques.Comment: 8 or 9 pages, LaTeX; uses aclap.sty, epsf.te

Combined Parsing Based on Grammar Systems

Tato práce se zabývá kombinovanou syntaktickou analýzou založenou na gramatických systémech. Zavádí klasické modifikované metody gramatických systémů. Nejprve budou teoreticky popsané a v další části implementované v syntaktickém analyzátoru. Základem analyzátoru je CD gramatický systém. Implementace využívá rekursivní sestup a precedenční analýzu. Analyzátor je universální, použitelný pro jakékoli gramatické systémy založené na bezkontextových a některých ne bezkontextových.This thesis deals with a combined parsing based on grammar systems. Introduces modified method of classical grammar systems. At first they will be theoretically described and in the next part they will be implemented for parsing. The basis for the parser is a cooperating distributed grammar system. Implementation uses recursive method and case analysis. The parser is universal, applicable to any grammar systems based on context-free and some not context-free.

On the number of components in cooperating distributed grammar systems

AbstractIt is proved that the number of components in context-free cooperating distributed (CD) grammar systems can be reduced to 3 when they are working in the so-called sf-mode of derivation, which is the cooperation protocol which has been considered first for CD grammar systems. In this derivation mode, a component continues the derivation until and unless there is a nonterminal in the sentential form which cannot be rewritten according to that component. Moreover, it is shown that CD grammar systems in sf-mode with only one component can generate only the context-free languages but they can generate non-context-free languages if two components are used. The sf-mode of derivation is compared with other well-known cooperation protocols with respect to the hierarchies induced by the number of components

Systems of Sequential Grammars Applied to Parsing

Tato práce zkoumá Gramatické systémy jako potenciálně silnější nástroj pro syntaktickou analýzu, nežli obyčejné gramatiky. Hlavním záměrem je aplikace teoretických modelů do praxe, vytvoření syntaktického analyzátoru. Jsou zavedeny nové metody zaměřené na determinizmus, a tím vyhnutí se zpětnému navracení při analýze. Základem analyzátoru je CD gramatický systém. Implementace využívá metodu prediktivní syntaktické analýzy, překlad řízený tabulkou a také rekurzi. Analyzátor je univerzální, použitelný pro jakékoliv LL-Gramatiky a jakékoliv gramatické systémy na nich založené.This thesis examines Grammar systems as the potentially more powerful tool for parsing as the simple grammars. The intention is to adapt theoretical models of grammar systems for parsing. New methods are introduced, with focus on determinism in order to prevent backtracking during parsing. The basis for the parser is a cooperating distributed grammar system. The implementation uses predictive, top-down parsing method, LL(1)Tables, and recursion as well. The parser is universal, usable for any LL-Grammar and for any grammar system based on them.