Strategic Argumentation is NP-Complete

In this paper we study the complexity of strategic argumentation for dialogue games. A dialogue game is a 2-player game where the parties play arguments. We show how to model dialogue games in a skeptical, non-monotonic formalism, and we show that the problem of deciding what move (set of rules) to play at each turn is an NP-complete problem

Colours, Corners And Complexity

"There is a philosophical question as to what one really sees". Wittgenstein's remark raises all sorts of questions: Does one see tables and chairs, people jumping up and down, their jumps, their sadness ? Does one see colours and forms, coloured forms, dynamic and static, that are above or to the left of other coloured forms ? If the latter, are these things one sees private entities or public entities as are, presumably, tables and chairs ? If both answers are legitimate (sometimes, or whenever we see ?) what are the relations between the people we see and the coloured forms that we also see ? In other words, is what is presented to me in my visual field private, public or partly private and partly public

Towards a Maude tool for model checking temporal graph properties

We present our prototypical tool for the verification of graph transformation systems. The major novelty of our tool is that it provides a model checker for temporal graph properties based on counterpart semantics for quantified m-calculi. Our tool can be considered as an instantiation of our approach to counterpart semantics which allows for a neat handling of creation, deletion and merging in systems with dynamic structure. Our implementation is based on the object-based machinery of Maude, which provides the basics to deal with attributed graphs. Graph transformation systems are specified with term rewrite rules. The model checker evaluates logical formulae of second-order modal m-calculus in the automatically generated CounterpartModel (a sort of unfolded graph transition system) of the graph transformation system under study. The result of evaluating a formula is a set of assignments for each state, associating node variables to actual nodes