Minimal Revision and Classical Kripke Models: First Results

Dynamic modal logics are modal logics that have statements of the form [?]?. The truth value of such statements, when evaluated in a pointed model (M, w), is determined by the truth value that ? takes in some or all of the pointed models (M , w) that stand in a relation ??? to (M, w). This paper introduces new dynamic operators that minimally revise finite classical Kripke models to make almost any satisfiable modal formula ? true. To this end, we define two minimal revision relations ?+?? and ?++??. The first revises only the valuation function whereas the second relation also changes the frame. Our approach is different from others in that (i) our revision expressions ? do not refer to abstract semantic objects such as accessibility relations or 'action models', (ii) we do not add extra semantic structure to our models, and (iii) yet we can make almost any formula true.