Abstract. We present the syntax and semantics for a multi-agent dialogue game protocol which permits argument over proposals for action. The protocol, called the PARMA Protocol, embodies an earlier theory by the authors of persuasion over action which enables participants to rationally propose, attack, and defend, an action or course of actions (or inaction). We present an outline of both an axiomatic and a denotational semantics, and discuss an implementation of the protocol for two human agents. 1

In this report we discuss the typology of dialogues given by Walton and Krabbe and offer a precise interpretation of them. We go on to discuss one of these dialogue types - persuasion - in the context of practical reasoning and the problems associated with such reasoning. We propose a perspective on practical reasoning as presumptive justification and critical questions, giving an extension to the account proposed by Walton [24]. This provides us with a foundation for a protocol, named PARMA, for a dialogue game based on this theory. We go on to give an axiomatic and denotational semantics for PARMA and discuss two implementations based on PARMA.

Abstract. We propose a representation of imperatives in computational systems, and a multi-agent dialogue protocol to argue over these. Our representation treats a command as a presumptive argument for an action to be executed by a designated agent, together with a set of associated critical questions whose answers may defeat the presumption. The critical questions enable the identification of attacks on the uttered command, and so can be used to specify a dialogue game protocol for participants to argue over the command. We present a formal syntax for part of the protocol, called CDP, and outline denotational semantics for both commands and for the protocol.

This paper investigates the properties of argumentation-based dialogues between agents. It takes a previously defined system by which agents can trade arguments, and examines how different classes of protocols for this kind of interaction can have profoundly different outcomes. Studying such classes of protocol, rather than individual protocols as has been done previously, allows us to start to develop a meta-theory of this class of interactions.

Abstract. This paper presents a novel approach to modelling embedded agent dialogues. It proposes a specific structure for the supporting information accompanying the arguments that agents exchange during a dialogue, it defines formally how this information relates to the agent theory, and assigns to it semantics that is associated to each of the atomic dialogue types of the Walton-Krabbe typology. This allows the formal definition of necessary and sufficient initiation and acceptance conditions of licit dialectical shifts that are necessary for the modelling of embedded agent dialogues. 1

Computer Science is currently undergoing a paradigm shift, from viewing computer systems as isolated programs to viewing them as dynamic multi-agent societies. Evidence of this shift is the significant effort devoted recently to the design and implementation of languages and protocols for communications and interaction between software agents. Despite this effort, no formal mathematical theory of agent interaction languages and protocols yet exists. We argue that such a theory needs to account for the semantics of agent interaction, and propose the first mathematical theory which does this. Our framework incorporates category-theoretic entities for the utterances made in an agent dialog and for the commitments incurred by those utterances, together with maps between these.

Novel architectures such as Grids have dynamic characteristics. Faults, nonexclusive access, and maintenance operations make resources come and go even during the execution time of applications. In order to deal with these events and continue the execution as good as possible, applications must be able to adapt to those changes of their execution environment. To do so, we propose a model in which an application chooses a special point in the future of its execution path at which it is able to modify itself. In the specific case of parallel applications, the threads must agree on the point to choose. This article presents a negotiation-based approach for reaching such an agreement. It focuses on the distributed algorithm executed by the threads to find such a point. This algorithm is compared to works that has been done in areas of distributed consensus and dialogue protocols of agents.