Goal driven theorem proving using conceptual graphs and Peirce logic

The thesis describes a rational reconstruction of Sowa's theory of Conceptual Graphs. The reconstruction produces a theory with a firmer logical foundation than was previously the case and which is suitable for computation whilst retaining the expressiveness of the original theory. Also, several areas of incompleteness are addressed. These mainly concern the scope of operations on conceptual graphs of different types but include extensions for logics of higher orders than first order. An important innovation is the placing of negation onto a sound representational basis. A comparison of theorem proving techniques is made from which the principles of theorem proving in Peirce logic are identified. As a result, a set of derived inference rules, suitable for a goal driven approach to theorem proving, is developed from Peirce's beta rules. These derived rules, the first of their kind for Peirce logic and conceptual graphs, allow the development of a novel theorem proving approach which has some similarities to a combined semantic tableau and resolution methodology. With this methodology it is shown that a logically complete yet tractable system is possible. An important result is the identification of domain independent heuristics which follow directly from the methodology. In addition to the theorem prover, an efficient system for the detection of selectional constraint violations is developed. The proof techniques are used to build a working knowledge base system in Prolog which can accept arbitrary statements represented by conceptual graphs and test their semantic and logical consistency against a dynamic knowledge base. The same proof techniques are used to find solutions to arbitrary queries. Since the system is logically complete it can maintain the integrity of its knowledge base and answer queries in a fully automated manner. Thus the system is completely declarative and does not require any programming whatever by a user with the result that all interaction with a user is conversational. Finally, the system is compared with other theorem proving systems which are based upon Conceptual Graphs and conclusions about the effectiveness of the methodology are drawn

Order and structure in syntax I

This book reconsiders the role of order and structure in syntax, focusing on fundamental issues such as word order and grammatical functions. The first group of papers in the collection asks what word order can tell us about syntactic structure, using evidence from V2, object shift, word order gaps and different kinds of movement. The second group of papers all address the issue of subjecthood in some way, and examine how certain subject properties vary across languages: expression of subjects, expletive subjects, quirky and locative subjects. All of the papers address in some way the tension between modelling what can vary across languages whilst improving our understanding of what might be universal to human language

Word order and syntactic structure

This book reconsiders the role of order and structure in syntax, focusing on fundamental issues such as word order and grammatical functions. The first group of papers in the collection asks what word order can tell us about syntactic structure, using evidence from V2, object shift, word order gaps and different kinds of movement. The second group of papers all address the issue of subjecthood in some way, and examine how certain subject properties vary across languages: expression of subjects, expletive subjects, quirky and locative subjects. All of the papers address in some way the tension between modelling what can vary across languages whilst improving our understanding of what might be universal to human language

Un modèle uniforme pour la modélisation et la métamodélisation d'une mémoire d'entreprise

Thèse diffusée initialement dans le cadre d'un projet pilote des Presses de l'Université de Montréal/Centre d'édition numérique UdeM (1997-2008) avec l'autorisation de l'auteur

On Aspectualizers in English. A Corpus-Based Approach = Az angol aspektuális igék szemantikájának vizsgálata korpusznyelveszéti módszerekkel

Az angol aspektuális igék szemantikájának vizsgálata korpusznyelveszéti módszerekkel [On Aspectulalizers in English. A Corpus-based Approach] átfogó szemantikai elemzést nyújt az aspektuális igékről és igeneves szerkezeteikről. A könyv abból a feltételezésből indul ki, hogy a formabeli eltérések szemantikai különbséggel is járnak, feltevés, amelyet az elemzés korpusznyelvészeti adatokkal próbál igazolni. Ez az elképzelés szerint az aspektuális szerkezetek és tárgyas szerkezeteik közötti különbség egyrészt a to infinitive, valamint az -ing szerkezetek különböző szemantikai értékének, másrészt az aspektuális igék szemantikájának is tulajdonítható. Az elemzésben nagy hangsúlyt kapnak a begin+to infinitive, begin+ing, start+to infinitive, start+ing, continue+to infinitive, continue+ing, cease+to infinitive, go on+to infinive, go on+ing, cease+to infinitive, cease+ing konstrukciók. Ezen szerkezetek mellett más aspektuális igék (keep, keep on, go on, finish, end, complete és resume) szemantikai elemzését is kínálja a könyv

Teoria Básica das Estruturas Conceptuais

As Estruturas Conceptuais são um formalismo de representação de conhecimentos baseado em grafos, os chamados grafos conceptuais. A teoria foi inicialmente desenvolvida por John Sowa há dez anos. Desde então, uma comunidade científica cada vez mais ampla tem-na utilizado em muitas áreas de aplicação e propôs várias alterações à teoria original. Também está em desenvolvimento uma implementação estado-da-arte gratuita e, além disso, os grafos conceptuais foram adoptados num padrão ANSI em preparação. Apesar desta actividade não existe de facto uma definição formal, completa, consistente e revista da Teoria das Estruturas Conceptuais. Esta dissertação vem contribuir para essa definição ao estender, refinar e clarificar as noções básicas da teoria. A classificação dos grafos conceptuais em grafos sintacticamente correctos, grafos bem tipados, grafos ontologicamente correctos, chamados grafos canónicos, e grafos verdadeiros é a base da clarificação do significado das várias noções e serve de guia às extensões e aos refinamentos introduzidos. As principais extensões foram feitas no sistema de tipos e no esquema de dependências entre vértices de grafos, e o refinamento de quase todos os aspectos da teoria - em particular das regras de formação de grafos canónicos e das regras de inferência para os grafos verdadeiros - inclui o tratamento formal de algumas propostas informais de outros autores. [Conceptual Structures is a knowledge representation formalism based on graphs, the so called conceptual graphs. The theory was initially developed by John Sowa 10 years ago. Since then, it has been used by a growing scientific community in many application areas, and several changes to the original theory have been proposed. Furthermore, a freely available state-of-the-art implementation is under way and conceptual graphs were adopted by an ANSI standard currently in preparation. However, there still doesn't exist a complete, consistent and revised formal definition of Conceptual Structures Theory. This thesis extends, refines and clarifies the basic notions of the theory, thus contributing to its redefinition. The classification of conceptual graphs into syntactically correct graphs, well-typed graphs, ontologically correct graphs, called canonical graphs, and true graphs is the basis for the clarification of the notions' meaning, and it is the guideline for introducing extensions and making refinements. The main extensions proposed regard the type system and the dependencies among graph nodes. The refinements cover almost every aspect of the theory – particularly the formation rules for canonical graphs and the inference rules for true graphs – and include the formal treatment of some informal proposals done by other authors.

Modélisation pour la gestion de modèles

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal