Anytime Approximations of Classical Logic from Above (original) (raw)

In this article we present s 1 , a family of logics that is useful to disprove propositional formulas by means of an anytime approximation process. The systems follows the paradigm of a parameterized family of logics established by Schaerf's and Cadoli's system S 1. We show that s 1 inherits several of the nice properties of S 1 , while presenting several attractive new properties. The family s 1 deals with the full propositional language, has a complete tableau proof system which provides for incremental approximations; furthermore, it constitutes a full approximation of classical logic from above, with an approximation process with better relevance and locality properties than S 1. When applied to clausal inference, s 1 provides a strong simplification method. An application of s 1 to model-based diagnosis is presented, demonstrating how the solution to this problem can benefit from the use of s 1 approximations.