Vardanyan's Theorem states that the set of PA-valid principles of Quantified Modal Logic, QML, is complete 0 2. We generalize this result to a wide class of theories. The cru...
ABSTRACT. In [CON 06b] we introduced the algorithm SQEMA for computing first-order equivalents and proving canonicity of modal formulae, and thus established a very general corresp...
We give a sound and complete propositional S5 tableau system of a particularly simple sort, having an easy completeness proof. It sheds light on why the satisfiability problem for...
An interpolation theorem holds for many standard modal logics, but first order S5 is a prominent example of a logic for which it fails. In this paper it is shown that a first orde...