Complete Types in an Extension of the System AF2

International audienceIn this paper, we extend the system AF2 in order to have the subject reduction for the $\beta\eta$-reduction. We prove that the types with positive quantifiers are complete for models that are stable by weak-head expansion

Regression in Modal Logic

In this work we propose an encoding of Reiter’s Situation Calculus solution to the frame problem into the framework of a simple multimodal logic of actions. In particular we present the modal counterpart of the regression technique. This gives us a theorem proving method for a relevant fragment of our modal logic