Abstract not found

Architecture The Alma Abstract Architecture (AAA) is the virtual architecture used during the intermediate code generation phase of the Alma-0 compiler. The AAA combines the features of the abstract machines for imperative languages and for logic programming languages. The compiler compiles the Alma-0 programs into AAA programs. In a second phase the AAA instructions are translated into C statements. As the Alma-0 language itself, the AAA aims to combine the best of both worlds; elements were taken from virtual machines used to compile imperative languages (in particular the RISC architecture described in Wirth [1996, pp. 55--59], and from the WAM machine used to compile a logical language (see Ait-Kaci [1991]). Still, the AAA resembles most the virtual machines used in the compilation of imperative languages. The additions made to provide for the extensions of the Alma-0 language are ---the failure handling instructions ONFAIL, FAIL, 40 \Delta Krzysztof R. Apt et al ---the log ...

In this paper we discuss the treatment ofvariables in dynamic semantics. Referent systems are introduced as a exible mechanism for working with variables. In a referent system we carefully distinguish the variables themselves both from the machinery by which wemanipulate them|their names|and from the information that we store in them|their values. It is shown that the referent systems provide a natural basis for dynamic semantics. The semantics with referent systems is compared with the familiar formalisms in dynamic semantics, DRT and DPL.

this paper is to combine within the same logic the dynamic account of variable binding from Groenendijk and Stokhof (1991a) with the dynamic account of epistemic updating from Veltman (1991), thus combining the useful features of Dynamic Predicate Logic (DPL) with those of Update Logic (UL). At the end of the paper we will briefly look at further extensions along other score-keeping dimensions. The DPL features provide a compositional treatment of anaphoric binding, while UL provides us with a treatment of epistemic modalities. By combining the two, our logic provides a suitable framework for the representation of natural language texts involving unbound anaphora and epistemic operators, and the interplay between those. Consider the following example texts. A man walked out. Maybe he was angry. (1) If a man walks out, then maybe he is angry. (2) The semantic analysis of these example texts poses a combination of two problems. The pronoun `he' must be linked to its antecedent; in the first example this is difficult because the antecedent is in a different sentence, while the second example poses the problem of getting the universal reading for the antecedent together with the intended anaphoric link. The adverb `maybe' intuitively acts as a consistency check on the piece of discourse that it has scope over. Its use in the two example texts above makes intuitive sense, but the next example illustrates that it can also serve to rule out anaphoric links. Maybe a man walked out.

this paper adds one more system to the existing stock. It o#ers a semantics for the language of modal predicate logic, which is new, not in the sense that it proposes a new ontology as an alternative to the possible world paradigm, but new because it characterizes the meaning of a sentence in terms of its information change potential rather than its truth conditions. What we hope to show is that this dynamic twist sheds new light on old # . We owe a special thanks to Paul Dekker. The present paper builds heavily on the last chapter of his thesis. His comments on various stages of the work reported here have prevented us from making many mistakes. For the remaining ones we take the blame. Maria Alloni and Jelle Gerbrandy also provided useful feed-back. Earlier versions of the paper were presented on various occasions. The first of these was the Workshop on Tense and Modality (Columbus, Ohio, July 1993). For their helpful comments, we thank the participants of that workshop, and of other events where we talked about this material. The paper will appear in D. Westerstahl & J. Seligman, Language, Logic and Computation: The 1994 Moraga Proceedings, Stanford: CSLI. It is an extended abstract of a longer paper, `Update semantics for modal predicate logic', by the same authors.

Abstract not found

Logical frameworks for analysing the dynamics of information processing abound [4, 5, 8, 10, 12, 14, 20, 22]. Some of these frameworks focus on the dynamics of the interpretation process, some on the dynamics of the process of drawing inferences, and some do both of these. Formalisms galore, so it is felt that some conceptual streamlining would pay off. This paper is part of a larger scale enterprise to pursue the obvious parallel between information processing and imperative programming. We demonstrate that logical tools from theoretical computer science are relevant for the logic of information flow. More specifically, we show that the perspective of Hoare logic [13, 18] can fruitfully be applied to the conceptual simplification of information flow logics. Part one of this program consisted of the analysis of `dynamic interpretation' in this way, using the example of dynamic predicate logic [10]; the results were published in [7]. The present paper constitutes the second part of the ...

The information state of an agent is changed when a text (in natural language) is processed. The meaning of a text can be taken to be this information state change potential. The inference of a consequence make explicit something already implicit in the premises -- i.e. that no information state change occurs if the (assumed) consequence text is processed after the (given) premise texts have been processed. Elementary logic (i.e. first-order logic) can be used as a logical representation language for texts, but the notion of a information state (a set of possibilities -- namely first-order models) is not available from the object language (belongs to the mete language). This means that texts with other texts as parts (e.g. propositional attitudes with embedded sentences) cannot be treated directly. Traditional intensional logics (i.e. modal logic) allow (via modal operators) access to the information states from the object language, but the access is limited and interference with (extensional) notions like (standard) identity, variables etc. is introduced. This does not mean that the ideas present in intensional logics will not work (possibly improved by adding a notion of partiality) , but rather that often a formalisation in the simple type theory (with sorts for entities and indices making information states first class citizens -- like individuals) is more comprehensible, flexi- ble and logically well-behaved.

• Some challenging properties of temporal modification (Pratt and Francez, 2001;

Abstract not found