The Design and Implementation of the GraPE Graphical Proof Editor

We present GraPE, a graphical proof editor that strives to provide a unified point-and-click interface for a variety of existing theorem provers and supports advanced proof editing features. It strictly separates the graphical user interface responsible for displaying the derivation being worked on from the actual proof engine, yielding a flexible and powerful theorem proving environment. Unlike many other proof editors, GraPE not only supports inference rules for incrementally building a derivation but also more complex proof generation and manipulation operations, such as automatic proof search and elimination of admissible rules. GraPE provides particularly strong support for the calculus of structures and for integration with the Maude language. We show how this support can be leveraged to quickly and easily obtain a graphical theorem prover for system KSg for classical propositional logic.