As an alternative to planning, an approach to high-level agent control based on concurrent program execution is considered. The language includes facilities for prioritizing the concurrent execution, interrupting the execution when certain conditions become true, and dealing with exogenous actions. The language di ers from other procedural formalisms for concurrency in that the initial state can be incompletely speci ed and the primitive actions can be user-de ned by axioms in the situation calculus. In a companion paper, a formal de nition in the situation calculus of such a programming language is presented and illustrated with detailed examples. In this paper, the mathematical properties of the programming language are explored. 1

The ability to reason about action and change has long been considered a necessary component for any intelligent system. Many proposals have been offered in the past to deal with this problem. In this paper, we offer a new approach to belief change associated with performing actions that addresses some of the shortcomings of these approaches. In particular, our approach is based on a well-developed theory of action in the situation calculus extended to deal with belief. Moreover, our account handles nested belief, belief introspection, mistaken belief, and handles belief revision and belief update together with iterated belief change. 1

The Cognitive Agents Specification Language (CASL) is a framework for specifying multiagent systems. It has a mix of declarative and procedural components to facilitate the specification and verification of complex multiagent systems. In this paper, we describe CASL and a verification environment (CASLve) for it based on the PVS verification system. We give an example of a multiagent meeting schedulerapplication specified with CASL. To illustrate the verification system, we discussa proof we carried out in it, namely, that all bounded-loop CASL specifications terminate. Categories and Subject Descriptors I.2.11 [Artificial Intelligence]: Distributed Artificial Intelligence—multiagent systems; D.2.1 [Software Engineering]:

Abstract. We propose an approach to reasoning about conversation protocols within the framework of a logic-based agent language. We show how to embed a theory of communicative actions in the framework of a modal logic of action and beliefs, to specify software agents that, situated in a multi-agent environment, can interact with one another by a speech act based communication mechanism. Agents have their own local beliefs on the world and on the other agents mental state. Complex communicative behaviors can be specified as conversation protocols, and agents can reason on the belief dynamics caused by communications, before committing to a given interaction. 1 Introduction and

In this work, we face the problem of web service composition, arguing the importance of the inclusion, in a web service description, of the high-level communication protocol used by a service to interact with a client. The work is set in the same multi-agent research area from which DAML-S is derived: reasoning about actions and about the change produced by actions on the world. In this perspective web services are viewed as actions, either simple or complex, characterized by preconditions and effects. In our proposal, interaction is interpreted as the effect of communicative action execution, so that it can be reasoned about. Keywords: Web-service composition, reasoning about actions, conversation protocols, modal logic languages.

A team of agents is jointly able to achieve a goal if despite any incomplete knowledge they may have about the world or each other, they still know enough to be able to get to a goal state. Unlike in the single-agent case, the mere existence of a working plan is not enough as there may be several incompatible working plans and the agents may not be able to choose a share that coordinates with those of the others. Some formalizations of joint ability ignore this issue of coordination within a coalition. Others, including those based on game theory, deal with coordination, but require a complete specification of what the agents believe. Such a complete specification is often not available. Here we present a new formalization of joint ability based on logical entailment in the situation calculus that avoids both of these pitfalls.

In this paper, we describe the Cognitive Agents Specification Language (CASL), and exhibit its characteristics by using it to model the multiagent feature interaction resolution system described by Griffeth and Velthuijsen [7]. We discuss the main features of CASL that make it a useful language for specifying and verifying multiagent systems. CASL has a nice mix of declarative and procedural elements with a formal semantics to facilitate the verification of properties of CASL specifications.

Abstract. In this paper, we identify some problems with current formalizations of conditional commitments, i.e. commitments to achieve a goal if some condition becomes true. We present a solution to these problems. We also formalize two types of communicative actions that can be used by an agent to request another agent to achieve a goal or perform an action provided that some condition becomes true. Our account is set within ECASL [7], a framework for modeling communicating agents based on the situation calculus. 1

tion: an example personal assistant a at a cinema where they show the movie "Akira" but it is requested by the user to communicate his credit card number Two different constraints: . a ticket to a cinema where they show the movie "Akira": goal to achieve . to communicate the credit card number: constraint about the way in which the interaction should be carried on We claim that a better personalization can be achieved by allowing agents to reason also about protocols followed by web about interaction for personalizingweb service fruition -- about conversations and interaction . does not allow to describe explicitly high-level interaction, concerning behavior . to the requester belief state and make rational assumptions on the change caused to the service provider beliefs . particular, DAML-S does not allow to describe the communicating with its clients or partners about interaction for personalizingweb service fruition -- this . face the problem of describing and

Abstract. We present an approach to reasoning about conversations within the framework of a logic-based agent language. Our agent theory isbasedonamodallogicofactionsandbeliefsandpermitstherepresentation of communicative acts and conversation protocols, allowing agents to reason about them before their execution. The work is framed in a world wide web context, in which we show how reasoning about the interaction with web service providers can be exploited for personalizing the service fruition. 1