Work on the semantics of questions has argued that the relation between a question and its answer(s) can be cast in terms of logical entailment. In this paper, we demonstrate how computational systems designed to recognize textual entailment can be used to enhance the accuracy of current open-domain automatic question answering (Q/A) systems. In our experiments, we show that when textual entailment information is used to either filter or rank answers returned by a Q/A system, accuracy can be increased by as much as 20 % overall. 1

In a dynamic and open environment negotiation protocols cannot be known beforehand. We propose a methodology for constructing exible negotiation protocols based on joint actions and dialogue games. We view negotiation as a combination of joint actions. Simple dialogue games that consist of initiatives followed by responses function as `recipes for joint action' from which larger interactions can be constructed coherently.

The alleged opposition between dialogue games and plans and goals as approaches to the study of natural language dialogue is false; the two approaches are complementary. On the one hand, plans and goals may function as a semantics to interaction patterns studied as dialogue games. On the other hand, dialogue games are `compiled-out' recipes for joint action. This claim is illustrated by a dialogue model for inquiry and transaction that uses aspects of both approaches. 1. Introduction Dialogue models of a more or less formal nature are needed for the design and evaluation of natural language dialogue systems. With respect to such models `dialogue engineers' can design a system for a particular application and later assess its performance with respect to the specifications (Hulstijn, 2000; Bernsen et al., 1998). Three aspects need to be modeled: the information structure of the objects and attributes that play a role in the application domain, the task structure of the available action...

Questions are different from statements, but they are just as important in driving reasoning, communication, and general processes of investigation. The first logical studies merging questions and propositions seem to have come from the Polish tradition: cf. [24]. A forceful modern defender of

This paper gives a characterisation of dialogue properties which are argued to be related to the usability of dialogue systems: effectiveness, effciency, transparency and a number of properties that have to do with coherence. Such properties can be used as guidelines in dialogue design, but also as aspects to test for in verification and validation.

Abstract. We implement Groenendijk and Stokhof’s partition semantics of questions in a simple question answering algorithm. The algorithm is sound, complete, and based on tableau theorem proving. The algorithm relies on a syntactic characterization of answerhood: Any answer to a question is equivalent to some formula built up only from instances of the question. We prove this characterization by translating the logic of interrogation to classical predicate logic and applying Craig’s interpolation theorem. 1 The Partition Theory of Questions An elegant account of the semantics of natural language questions from a logical and mathematical perspective is the one provided by Groenendijk and Stokhof [8]. According to them, a question denotes a partition of a logical space of possibilities. In this section, we give a brief summary of this influential theory, using a notation slightly different from Groenendijk’s presentation [7]. A question is essentially a first order formula, possibly with free variables.

Update Semantics —more than related dynamic frameworks such as DRT — offers a promise of being able to integrate that part of pragmatics that is rule governed with semantics.

Abstract. We propose a novel interpretation of natural-language questions using a modal predicate logic of knowledge. Our approach brings standard model-theoretic and proof-theoretic techniques from modal logic to bear on questions. Using the former, we show that our interpretation preserves Groenendijk and Stokhof’s answerhood relation, yet allows an extensional interpretation. Using the latter, we get a sound and complete proof procedure for the logic for free. Our approach is more expressive; for example, it easily treats complex questions with operators that scope over questions. We suggest a semantic criterion that restricts what natural-language questions can express. We integrate and generalize much previous work on the semantics of questions, including Beck and Sharvit’s families of subquestions, non-exhaustive questions, and multi-party conversations.

Analyses developed so far, failed to provide an adequate semantics for the interpretation of which-interrogatives of the form \Which P are Q?". In this paper a new logical language is developed, where whichinterrogatives are expressed by universally quantifying over conditional interrogatives. Furthermore, a new semantic notion is introduced, that of an alternative. By means of the latter an adequate interpretation is given and shortcomings concerning answerhood and trivial interrogatives are suciently dealt with. 3 Contents 1 Introduction 5 2 The propositional logical case 6 2.1 Simple yes/no-interrogatives . . . . . . . . . . . . . . . . . . 6 2.1.1 The syntax of simple yes/no-interrogatives . . . . . 6 2.1.2 The semantics of simple yes/no-interrogatives . . . . 7 2.2 Adding conditional interrogatives . . . . . . . . . . . . . . . 11 2.2.1 The syntax of conditional interrogatives . . . . . . . 11 2.2.2 The semantics of conditional interrogatives . . . . . 12 2.2.3 Another approach...

Abstract. Groenendijk and Stokhof (1984, 1996; Groenendijk 1999) provide a logically attractive theory of the semantics of natural language questions, commonly referred to as the partition theory. Two central notions in this theory are entailment between questions and answerhood. For example, the question Who is going to the party? entails the question Is John going to the party?, and John is going to the party counts as an answer to both. Groenendijk and Stokhof define these two notions in terms of partitions of a set of possible worlds. We provide a syntactic characterization of entailment between questions and answerhood. We show that answers are, in some sense, exactly those formulas that are built up from instances of the question. This result lets us compare the partition theory with other approaches to interrogation—both linguistic analyses, such as Hamblin’s and Karttunen’s semantics, and computational systems, such as Prolog. Our comparison separates a notion of answerhood into three aspects: equivalence (when two questions or answers are interchangeable), atomic answers (what instances of a question count as answers), and compound answers (how answers compose). We would like to thank Patrick Blackburn, Paul Dekker, Jeroen Groenendijk, Maarten Marx, Robert van Rooy, Stuart Shieber, and the anonymous referees for their useful