Computing consensus: A logic for reasoning about deliberative processes based on argumentation

We consider multi-agent argumentation, where each agent's view of the arguments is encoded as an argumentation framework (AF). Then we study deliberative processes than can occur on this basis. We think of a deliberative process as taking the shape of a stepwise aggregation of a single joint AF, and we are interested in reasoning about the space of possible outcomes. The only restriction we place on deliberative processes is that they should satisfy faithfulness, a postulate amounting to requiring that whenever deliberation leads to a new relationship being introduced between two arguments, this relationship is endorsed by at least one participating agent. We use modal logic to reason about the resulting deliberative structures, and we provide some technical results on model checking. We also give an example and suggest some directions for future work.