Deciding the guarded fragments by resolution

The guarded fragment is a fragment of first-order logic that has been introduced for two main reasons: First, to explain the good computational and logical behavior of propositional modal logics. Second, to serve as a breeding ground for well-behaved process logics. In this paper we give resolution-based decision procedures for the guarded fragment and for the loosely guarded fragment (sometimes also called pairwise guarded fragment). By constructing an implementable decision procedure for the guarded fragment and for the loosely guarded fragment, we obtain an effective procedure for deciding modal logics that can be embedded into these fragments. The procedures have been implemented in the theorem prover Bliksem.