Rasiowa-Sikorski Deduction Systems: A Handy Tool for Computer Science Logics

A Rasiowa-Sikorski system is a sequence-type formalization of logics based on building decomposition trees of formulae labelled with sequences of formulae. Proofs are nite decomposition trees with leaves having \fundamental", valid labels. The system is dual to the tableau system. The author gives examples of applying the R-S formalism to various C.S and A.I. logic, including a logic for reasoning about relative similarity, a three-valued software speciication logic with McCarthy's connectives, and a logic for nondeterministic speciications. As a new result, an R-S system for many-sorted rst order logic with possibly empty carriers of some sorts is developed.