Presentation of Proofs in an Equational Calculus

Abstract

One of the main reasons why computer generated proofs are not widely accepted is often their complexity and incomprehensibility. Especially proofs of mathematical theorems with equations are normally presented in an inadequate and not intuitive way. Often completion and rewrite proofs are only given in the form of a program trace. This is even more of a problem for the presentation of inferences drawn by automated reasoning components in other AI systems. For first order logic, proof transformation procedures have been designed in order to structure proofs and state them in a formalism that is more familiar to human mathematicians. In this report we present a method to handle equational proofs in such systems. To this end equation solution graphs are introduced to represent paramodulation or rewrite proofs. In the process of transforming these proofs into proofs with equation chains, the inherent structure can also be extracted by exploiting topological properties similar to those of refutation graphs in the pure first order case.