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This paper investigates a new representation format for dynamic discourse in DRT, where contextual dynamics is modeled in terms of update conditions. This new representation format is motivated by the study of context dependence in modal constructions, in particular by serious problems besetting earlier approaches to modality and modal subordination in DRT. We present an alternative DRT analysis that provides a unified analysis of relative modality

This book deals with the semantics of natural language expressions that are commonly taken to refer to individuals: pronouns, definite descriptions and proper names. It claims, contrary to previous theorizing, that they all have a common syntax and semantics, roughly that which is currently associated by philosophers and linguists with definite descriptions as construed in the tradition of Frege. As well as advancing this proposal, I hope to achieve at least one other aim, that of urging semanticists dealing with pronoun interpretation, in particular donkey anaphora, to consider a wider range of theories at all times than is sometimes done at present. I am thinking particularly of the gulf that seems to have emerged between those who practice some version of dynamic semantics (including DRT) and those who eschew this approach and rely on some version of the E-type analysis for donkey anaphora (if they consider this phenomenon at all). In my opinion there is too little work directly comparing the claims of these two schools (for that is what they amount to) and testing them against the data in the way that any two rival theories might be tested. (Irene Heim’s 1990 article in Linguistics and Philosophy does this, and

In this paper, reasoning with ambiguous representations is explored in a formal way, with ambiguities at the level of propositions in propositional logic and predicate logic, and ambiguous representations of scopings in predicate logic as the main examples. First a version of propositional logic with propositional ambiguities is presented and a sequent axiomatization for it is given. This is then extended to predicate logic. Next, predicate logic with scope ambiguities is introduced and discussed, and again a sequent calculus for it is proposed. The conclusion connects the results to natural language semantics, and briefly compares them with existing logics of ambiguity. An appendix gives completeness proofs for our versions of ambiguous propositional and predicate logic. AMS Subject Classification (1991): 03B65, 03B80, 68S05, 68T30, 92K20. CR Subject Classification (1991): F.3.1, F.3.2, I.2.1, I.2.4, I.2.7. Keyword and Phrases: Semantics of Natural Language, Reasoning with Underspec...

Modal logic becomes action logic by adding programs as in propositional dynamic logic or the µ-- calculus. Modal languages can be seen as decidable fragments of first-order logic that admit a natural bisimulation, and hence enjoy a good model theory. Recently, much stronger 'guarded fragments' of firstorder logic have been identified that enjoy the same pleasant features. The latter can serve as richer action languages as well. We will develop the logic of guarded fragments as a form of process theory. ln particular, moving from sequential to parallel process operations correlates with moving to first-order fragments that are close to, or perhaps just over the decidable--undecidable fence. 1 The modal dynamics of actions We will start by reviewing the basics. Standard polymodal logic is a decidable fragment of the first-order logic of process graphs (labeled transition systems, Kripke models). It can be characterized semantically as consisting, up to logical equivalence, of those firs...

Standard generative linguistic theory, which uses discrete symbolic models of cognition, has some strengths and weaknesses. It is strong on providing a network of outposts that make scientific travel in the jungles of natural language feasible. It is weak in that it currently depends on the elaborate and unformalized use of intuition to develop critical supporting assumptions about each data point. In this regard, it is not in a position to characterize natural language systems in the lawful terms that ecological psychologists strive for. Connectionist learning models offer some help: They define lawful relations between linguistic environments and language systems. But our understanding of them is currently weak, especially when it comes to natural language syntax. Fortunately, symbolic linguistic analysis can help connectionism if the two meet via dynamical systems theory. I discuss a case in point: Insights from linguistic explorations of natural language syntax appear to have identified information structures that are particularly relevant to understanding ecologically appealing but analytically mysterious connectionist learning models. This article is concerned with the relation between discrete, symbolic systems of the

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... this article. BAT is reformulated to meet requirements for computational implementation, which include operations on discourse representation structures (renaming and merging), the representation of presuppositions (allowing for selective binding and determining free and bound variables), and a formulation of the acceptability constraints imposed by BAT. An efficient presupposition resolution algorithm is presented, and several further improvements such as preferences for binding and accommodation are discussed and integrated in this algorithm. Finally, innovative use of first-order theorem provers to carry out consistency checking of discourse representations is investigated.

This paper focuses on the semantics of implicit arguments and compares it with that of explicit indefinites with which they can be truth-conditionally paraphrased. It is shown that once the discourse-potential of expressions is taken into account, the semantics of implicit arguments differs from their indefinite explicit counterparts. They are shown to be semantically identical to a particular kind of non-quantificational NP (a-definites) which are characterized by their inability to serve as antecedents for future reference. A model of this behavior of implicit arguments, it is argued, follows naturally from the underlying assumption of Discourse Representation Theory that semantic representations must include two kinds of information, a set of available discourse markers and a set of predicative conditions. Because implicit arguments satisfy a predicate's argument positions without introducing discourse markers into the Discourse Representation Structure of a sentence, they cannot serve as the antecedent of definite pronouns. When they do enter into anaphoric relations it is not through discourse markers equality clauses, but instead is the result of either lexical identification of variables (via semantic detransitivization or

states of mind, etc. Natural language semantics, as a theory of meaning, determines what the meanings of words of the language are and how to semantically combine elements of a language to build up complex meanings. These meanings are most often represented as formulas in a logical language. Computational semantics investigates the computational properties that formal semantic theories need to enjoy to be applicable to real-world problems. Most approaches in formal semantics are evaluated with respect to criteria like expressiveness, explanatory adequacy, and generality, whereas typical criteria for evaluating approaches in computational semantics include coverage, robustness, eciency, and user-friendliness. Coverage measures the amount of phenomena that can described by a semantic theory. Although coverage should be regarded as a criterion f