Linear Logic for Meaning Assembly

Semantic theories of natural language associate meanings with utterances by providing meanings for lexical items and rules for determining the meaning of larger units given the meanings of their parts. Meanings are often assumed to combine via function application, which works well when constituent structure trees are used to guide semantic composition. However, we believe that the functional structure of Lexical-Functional Grammar is best used to provide the syntactic information necessary for constraining derivations of meaning in a cross-linguistically uniform format. It has been difficult, however, to reconcile this approach with the combination of meanings by function application. In contrast to compositional approaches, we present a deductive approach to assembling meanings, based on reasoning with constraints, which meshes well with the unordered nature of information in the functional structure. Our use of linear logic as a `glue' for assembling meanings allows for a coherent treatment of the LFG requirements of completeness and coherence as well as of modification and quantification.Comment: 19 pages, uses lingmacros.sty, fullname.sty, tree-dvips.sty, latexsym.sty, requires the new version of Late

Nominal juxtaposition in Australian languages: An LFG analysis

It is well known that Australian languages make heavy use of nominal juxtaposition in a wide variety of functions, but there is little discussion in the theoretical literature of how such juxtapositions should be analysed. We discuss a range of data from Australian languages illustrating how multiple nominals share a single grammatical function within the clause. We argue that such constructions should be treated syntactically as set-valued grammatical functions in Lexical-Functional Grammar (LFG). Sets as values for functions are well-established in LFG and are used in the representation of adjuncts, and also in the representation of coordination. In many Australian languages, coordination is expressed asyndetically, that is, by nominal juxtaposition with no overt coordinator at all. We argue that the syntactic similarity of all juxtaposed constructions (ranging from coordination through a number of more appositional relations) motivates an analysis in which they are treated similarly in the syntax, but suitably distinguished in the semantics. We show how this can be achieved within LFG, providing a unified treatment of the syntax of juxtaposition in Australian languages and showing how the interface to the semantics can be quite straightforwardly defined in the modular LFG approach. Copyright © Cambridge University Press 2009

Type-driven semantic interpretation and feature dependencies in R-LFG

Once one has enriched LFG's formal machinery with the linear logic mechanisms needed for semantic interpretation as proposed by Dalrymple et. al., it is natural to ask whether these make any existing components of LFG redundant. As Dalrymple and her colleagues note, LFG's f-structure completeness and coherence constraints fall out as a by-product of the linear logic machinery they propose for semantic interpretation, thus making those f-structure mechanisms redundant. Given that linear logic machinery or something like it is independently needed for semantic interpretation, it seems reasonable to explore the extent to which it is capable of handling feature structure constraints as well. R-LFG represents the extreme position that all linguistically required feature structure dependencies can be captured by the resource-accounting machinery of a linear or similiar logic independently needed for semantic interpretation, making LFG's unification machinery redundant. The goal is to show that LFG linguistic analyses can be expressed as clearly and perspicuously using the smaller set of mechanisms of R-LFG as they can using the much larger set of unification-based mechanisms in LFG: if this is the case then we will have shown that positing these extra f-structure mechanisms is not linguistically warranted.Comment: 30 pages, to appear in the the ``Glue Language'' volume edited by Dalrymple, uses tree-dvips, ipa, epic, eepic, fullnam

Structural Analysis of Narratives with the Coq Proof Assistant

Abstract. This paper proposes a novel application of Interactive Proof Assistants for studying the formal properties of Narratives, building on recent work demonstrating the suitability of Intuitionistic Linear Logic as a conceptual model. More specifically, we describe a method for modelling narrative resources and actions, together with constraints on the story endings in the form of an ILL sequent. We describe how well-formed narratives can be interpreted from cut-free proof trees of the sequent obtained using Coq. We finally describe how to reason about narratives at the structural level using Coq: by allowing to prove 2nd order properties on the set of all the proofs generated by a sequent, Coq assists the verification of structural narrative properties traversing all possible variants of a given plot

Proposta de sistema de diálogo textual independente de aplicação

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Ciência da ComputaçãoEste trabalho propoe uma abordagem para o desenvolvimento de um sistema de dialogo. Trata-se de um sistema computacional, uma interface para humanos interagirem de forma mais natural com aplicaçoes que fornecem serviços diversos, tais como: previsao de tempo, consulta de reservas, dentre outras. Para se entender a base de funcionamento desse tipo de sistema, sao apresentados os conceitos do processamento de linguagem natural, sistema de dialogo generico e alguns exemplos de sistemas de dialogo desenvolvidos, explicitando suas caracteristicas e aplicaçoes. Com base nos conceitos e experiencias comprovadas de sistemas anteriores, apresenta-se a especificaçao de um modelo de dialogo que possui dois componentes-chaves, a saber: um componente capaz de gerenciar o dialogo por meio de principios racionais e cooperativos e outro, cujo uso da noçao computacional de ontologia toma lugar na comunicaçao entre usuarios e aplicaçoes fornecedoras de serviços. Ao final deste trabalho a proposta de um sistema de dialogo e apresentada, entretanto sua implementaçao e apenas sugerida por um exemplo, visto que o desenvolvimento de um sistema de dialogo complet

Factores sintácticos y semánticos en el procesamiento del lenguaje

Tesis de la Universidad Complutense de Madrid, Facultad de Psicología, Departamento de Psicología Básica II (Procesos Cognitivos), leída el 13-07-2002Este trabajo se enmarca dentro de la Psicololingüística y del estudio de los Procesos Cognitivos. En particular nos ocupamos de la ambigüedad sintáctica referente a la adjunción de una cláusula de relativo y de la resolución anafórica, ambos fenómenos son claves dentro del procesamiento del lenguaje, a la hora de intentar determinar cuál es la arquitectura del sistema y cómo se utilizan los distintos tipos de información dentro del propio sistema, dado que el caracterizar los factores y principios que los determina los factores responsables del procesamiento sintáctico y del procesamiento semántico. En el primer bloque teórico se abordan las cuestiones básicas, revisaremos las teorías y postulados propuestos hasta la fecha, planteando a continuación las cuestiones críticas que son abordadas a lo largo de los dos bloques siguientes. En el bloque experimental se desarrollaron cuatro experimentos dos sobre resolución de la ambigüedad sintáctica, longitud de la clásula, esto en relación a la articulación tópico-foco en la oración (factor semántico) y diversos tipos de conectores. Se utilizan muestras de hablantes nativos de la lengua española y nativos del inglés realizando tares en español como segunda lengua. Los otros dos experimentos se ocupan de la resolución anafórica, de la resolución de los pronombres en castellano, estudiando la presencia o ausencia, tipo de especificadotes, distancia a los posibles referentes, elementos cuantificados y contrastivos. En el último bloque presentamos las conclusiones donde planteamos un modelo de principios estructurales de carácter universal, observando que las estrategias entre hablantes nativos se basan en estas estrategias mientras que los no nativos utilizan estrategias más lexicalistas.Depto. de Psicología Experimental, Procesos Cognitivos y LogopediaFac. de PsicologíaTRUEpu