Semantic categories underlying the meaning of ‘place’

This paper analyses the semantics of natural language expressions that are associated with the intuitive notion of ‘place’. We note that the nature of such terms is highly contested, and suggest that this arises from two main considerations: 1) there are a number of logically distinct categories of place expression, which are not always clearly distinguished in discourse about ‘place’; 2) the many non-substantive place count nouns (such as ‘place’, ‘region’, ‘area’, etc.) employed in natural language are highly ambiguous. With respect to consideration 1), we propose that place-related expressions should be classified into the following distinct logical types: a) ‘place-like’ count nouns (further subdivided into abstract, spatial and substantive varieties), b) proper names of ‘place-like’ objects, c) locative property phrases, and d) definite descriptions of ‘place-like’ objects. We outline possible formal representations for each of these. To address consideration 2), we examine meanings, connotations and ambiguities of the English vocabulary of abstract and generic place count nouns, and identify underlying elements of meaning, which explain both similarities and differences in the sense and usage of the various terms

Talking about Forests: an Example of Sharing Information Expressed with Vague Terms

Most natural language terms do not have precise universally agreed definitions that fix their meanings. Even when conversation participants share the same vocabulary and agree on taxonomic relationships (such as subsumption and mutual exclusivity, which might be encoded in an ontology), they may differ greatly in the specific semantics they give to the terms. We illustrate this with the example of `forest', for which the problematic arising of the assignation of different meanings is repeatedly reported in the literature. This is especially the case in the context of an unprecedented scale of publicly available geographic data, where information and databases, even when tagged to ontologies, may present a substantial semantic variation, which challenges interoperability and knowledge exchange. Our research addresses the issue of conceptual vagueness in ontology by providing a framework based on supervaluation semantics that explicitly represents the semantic variability of a concept as a set of admissible precise interpretations. Moreover, we describe the tools that support the conceptual negotiation between an agent and the system, and the specification and reasoning within standpoints

Classification, Individuation and Demarcation of Forests: Formalising the Multi-Faceted Semantics of Geographic Terms

Many papers have considered the problem of how to define "forest". However, as we shall illustrate, while most definitions capture some important aspects of what it means to be a forest, they almost invariably omit or are very vague regarding other aspects. In the current paper we address this issue, firstly by providing a definitional framework based on spatial and physical properties, within which one can make explicit the implicit variability of the natural language forest concept in terms of explicit parameters. Our framework explicitly differentiates between the functions of classification, individuation and demarcation that comprise the interpretation of predicative terms. Whereas ontologies have traditionally concentrated predominantly on classification, we argue that in many cases (especially in the case of geographic concepts) criteria for individuation (i.e. establishing how many distinct individual objects of a given type exist) and demarcation (establishing the boundary of an object) require separate attention, involve their own particular definitional issues and are affected by vagueness in different ways. We also describe a prototype Prolog system that illustrates how our framework can be implemented

Classification and Ambiguity: the Role of Definition in a Conceptual System

With the advent of the semantic web, the problem of ambiguity is becoming more and more urging. Semantic analysis is necessary for explaining and resolving some sorts of ambiguity by inquiring into the relation between possibilities of predication and definition of a concept in order to solve problems such as interpretation and ambiguity. If computing is now approaching such problems of linguistic analysis, what is worth inquiring into is how the development of linguistic studies can be useful for developing the theoretical background of ontologies. Our proposal is to develop a theory of definition alternative to the traditional metaphysical approach and the modern relativistic account. We interpret the ancient notion of essential definition in a dialectical perspective, and show how the dialectical definition by genus and difference corresponds to the semantic analysis of the definiendum. The dialectical definition is shown to be grounded on the deepest endoxa (shared knowledge) of a community, and to be the argumentatively strongest definition. After presenting the most common types of definition used in argumentation, the linguistic and logical characteristics of the notion of definition by genus and difference are set out in a pragmatic framework

A Computational Framework for Formalizing Rules and Managing Changes in Normative Systems

Legal texts are typically written in a natural language. However, a legal text that is written in a formal language has the advantage of being subject to automation, at least partially. Such a translation is not easy, and the matter is even more complex because the law changes with time, so if we formalized a legal text that was originally written in natural language, there is a need to keep track of the change. This thesis proposes original developments on these subjects. In order to formalize a legal document, we provide a pipeline for the translation of a legal text from natural to formal language and we apply it to the case of natural resources contracts. In general, adjectives play an important role in a text and they allow to characterize it: for this reason we developed a logical system aimed at reasoning with gradable adjectives. Regarding norm change, we provide an ontology to represent change in a normative system, some basic mechanisms by which an agent may acquire new norms, and a study on the problem of revising a defeasible theory by only changing its facts. Another contribution of this thesis is a general framework for revision that includes the previous points as specific cases

Modes of Concept Definition and Varieties of Vagueness ∗† Brandon Bennett, School of Computing, University of Leeds,

The paper considers the problem of defining concepts within formal ontologies. A number of distinct modes of definition are identified, which represent alternative viewpoints on the classification of objects. The nature of these modes is examined and interactions and correlations between them are considered. This analysis is used to characterise a number of key problems that confront the attempt to analyse the meanings of natural language concepts by means of a precise formal ontology. Some proposals are made as to how these problems might be overcome. It is argued that specification of precise formal semantics requires clear separation between aspects of meaning that are based on different modes of classification. But, to provide an adequate ontological framework to describe the semantics of natural language terms, additional formal apparatus is required to synthesise their meaning by combining the different modes. This meta-level ontological formalism must articulate the interactions between the different modes