Krifka and others have recently developed modal accounts of the GEN operator that allows multiple readings of a generic sentence to be represented. These modal accounts do not satisfactorily deal with the observation that the truth of a generic sentence may be relative to a particular context. This problem is addressed using a model of generics based on Barwise and Seligman's Channel Theory, a recently-developed mathematical model of information-flow that accounts for context and exceptions. The Channel Theoretic model possesses several important properties, which allow an analysis of some traditionally problematic issues in the semantics of generics. 1 Introduction We begin with a brief discussion of the existence of multiple readings for some generic sentences, showing how Krifka (1995) represents the semantics of such sentences, using the quantificational account of generics developed by Wilkinson (1986, 1991), Kratzer (1995) and Diesing (1988) and a modal account of the semanti...

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this paper appeared in the proceedings of that conference (Glasbey 1996), and in (Glasbey 1994a). The research is supported by an EPSRC postdoctoral fellowship. 1 Introduction Considerable effort has been expended over the last twenty-five years or so in attempting to capture the exact meaning of the English progressive. We will argue below that, while a great deal of progress has been made, no-one has yet produced an adequate account. In this paper we will present an analysis which, we argue, remedies some of the deficiencies. We will review some of the problems associated with pinning down exact truth conditions for progressive constructions. In particular, we will examine two recent accounts of the semantics of the progressive, those of Landman (1992) and Asher (1992). We argue that while neither account is completely satisfactory, both contain important insights which can be combined and made more precise in the treatment we develop based on Barwise and Seligman's Channel Theory (Barwise and Seligman 1994), a recent theory of information flow and reasoning with incomplete information. Our account is inspired in part by Hinrichs (1983), who gave an analysis of the progressive in terms of situation theoretic constraints (a precursor to some of the notions of channel theory), and Cooper (1985), who made further suggestions along these lines. We will argue that the notions of natural regularity and channel embodied in channel theory provide exactly what is needed to give an account of the progressive which is precisely expressed and explains the data. In particular, we will show how natural regularities, while related to "defaults" as used, for example, by Asher, are different in some significant respects which allow us to account for some examples that are problemati...

We argue that context plays an important role in the interpretation of generic sentences. The examples we use to demonstrate this have also been used to argue that normative approaches (upon which logics of normality are based) to generics have some fundamental problems related to scope. We use Barwise and Seligman's channel theory---a model of information-flow based on ideas from situation theory---as the basis for an analysis of generics that provides a context for each generic sentence and thereby avoids the problems raised. The channel-theoretic analysis provides the basis for a framework for reasoning both with generics (about the default properties of individuals) and about them (to infer new generics). Modelling the context of a generic also allows us to model the sort of misunderstandings that may occur in a dialogue, whereby a listener misinterprets the scope of an uttered generic sentence. 1 Generics and Context It is generally agreed that generic sentences are used to conv...

ing over X gives us a type corresponding to "being a dog in R". Now suppose we are are not interested in a particular R but in the type of "being a dog in some resource situation or other". We can express this by existentially quantifying over R, to give the type X 9 R R dog(X) which is the type corresponding to "being a dog in some or other resource situation", as we require. Thus the denotation of bare plurals differs from that of, say, proper names or pronouns which are taken in situation theory to denote parameters. Compare, for example, the representation for: (10) Fido barked. which is: S bark(X, T, P) R named(X, `Fido') Here, the "main" proposition is restricted by the proposition that a resource situation R supports the information that X is named `Fido'. The representation for: 7 See McNally 1995a for an independent but closely-related proposal that bare plurals in Spanish should be taken to refer to properties. 8 We ignore tense here, for simplicity. 9 We make the addit...

The paper develops a semantics for natural language interrogatives which identifies questions— the denotations of interrogatives—with propositional abstracts. The paper argues that a theory of Questions as Propositional Abstracts (QPA), is a simple, transparently implementable theory that has significant empirical coverage. However, until recently QPA has been abandoned in formal semantic treatments of questions, due to a number of significant problems QPA encountered when formulated within the type system of Montague Semantics. In recent work, Ginzburg and Sag provided a a situation theoretic implementation of QPA that succeeded in overcoming cerain of the original problems for QPA. However, Ginzburg and Sag’s proposal relied on a special purpose account of λ-abstraction, raising the question to what extent QPA can be sustained using standard notions of abstraction. In this paper such doubts are allayed by implementing QPA in a version of Type Theory that provides record types. These latter allow one to develop notions of simultaneous/vacuous abstraction with restrictions and an ontology with various ‘informational entities’. Moreover, the intrinsic polymorphism of this theory plays a crucial role in enabling the definition of a general type for questions, one of the main stumbling blocks for earlier versions of QPA. 1

ing from the nature of the states involved, we can specify the change that an atomic program a effects by means of a two place transition relation R a on a set of states. This perspective gives rise to the study of so-called transition systems. The most general style of reasoning about programs and transition system is found in propositional dynamic logics (Pratt [ Pratt, 1976 ] [ Pratt, 1980 ] , Harel [ Harel, 1984 ] ) and in algebras of processes (Hennessy [ Hennessy, 1988 ] ). Processes and transition systems are studied from the perspective of modal logic in Stirling [ Stirling, 1987 ] and Van Benthem and Bergstra [ Benthem and Bergstra, 1993 ] . Dynamic semantics can be put to use to stipulate relational denotations for propositions. In this perspective, a state of information is a set of possible worlds, and a program updates a state of information by removing the worlds incompatible with the new information. Thus, the semantics of language is defined in terms of its potential to...

In this document we discuss and evaluate some relevant recent research which aims at providing strategies for a general framework for computational semantics. The approaches considered can be broadly classified into three groups: operators, formal specification and semantic metatheory. Chapter 1 Operators 1.1 Introduction Briefly and informally the (semantic or syntactic) operators approach is based on the following idea: unlike in the traditional setup where syntactic and semantic representations are related to one another in a fairly direct fashion (e.g. in terms of associating syntactic composition rules with corresponding semantic rules) in the operator approach syntactic and semantic representations are related indirectly in terms of constructor operators. The operations associated with the operators then define the particulars of a syntax-semantics interface while the operators themselves are hoped to capture the more abstract and general properties of an interface or inter...

. Most optimisation techniques for theorem provers for first-order logic rely on static analysis of the problem statement. For intensional logics, such as static analysis cannot be relied on, since it is impossible to predict what literals may be introduced by the intensional rules. The current paper shows how to use a dynamic (run-time) version of one well-known static optimisation, and considers its relationship to the use of `relevance checking' in Satchmo. 1 A constructive intensional logic We have shown elsewhere [8, 3] how to extend [6]'s theorem prover Satchmo to cope with [9]'s property theory. Property theory is a highly intensional logic which, roughly speaking, allows you to perform unconstrained quantification over propositions and properties, but places constraints on the conditions under which the Tarski biconditional (xP ):t $ P t=x holds. This language has numerous potential applications: I use it primarily for reasoning about natural language semantics, becaus...