Constructing Craig Interpolation Formulas

A Craig interpolant of two inconsistent theories is a formula which is true in one and false in the other. This paper gives an efficient method for constructing a Craig interpolant from a refutation proof which involves binary resolution, paramodulation, and factoring. This method can solve the machine learning problem of discovering a first order concept from given examples. It can also be used to find sentences which distinguish pairs of nonisomorphic finite structures.