Protein: A PROver with a Theory Extension INterface [chapter]

Peter Baumgartner, Ulrich Furbach
1994 Lecture Notes in Computer Science  
PROTEIN (PROver with a Theory Extension INterface) is a PTTPbased first order theorem prover over built-in theories. Besides various standardrefinements known for model elimination, PROTEIN also offers a variant of model elimination for case-based reasoning and which does not need contrapositives. PROTEIN is a complete theorem prover for first order clause logic. It is characterized by the following features: -PROTEIN is based on the PTTP implementation technique [Sti88] for model elimination
more » ... ov69]. -PROTEIN offers alternative inference rules for case analysis [Lov87, BF93]. In this setting no contrapositives are needed, and hence the system is well suited as an interpreter for disjunctive logic programming. -PROTEIN includes theory reasoning [Sti85, Bau92, Bau94] in a very general way. An auxiliary program can be used to derive a suitable background reasoner from a given Horn theory in a fully automatic way. -PROTEIN includes several calculus refinements and flags. The idea of the PTTP implementation technique ("Prolog Technology Theorem Prover") [Sti88] is to view Prolog as an "almost complete" theorem prover, which has to be extended by only a few ingredients in order to handle the non-Horn case. By this technique the WAM-technology and other benefits of optimizing Prolog compilers are accessible to theorem proving. A disadvantage of PTTP, according to Stickel ([Sti90]), is that "the high inference rate can be overwhelmed by its exponential search space" and therefore PTTP might be well suited for easy problems whereas "it is unsuitable for many difficult theorems for which more conventional theorem provers have demonstrated success". Our system proves that PTTP can be used even for many challenging problems from the theorem proving literature if PTTP is understood only as a kernel system, which has to be augmented by additional features, like theory handling or case analysis. This is done in PROTEIN. £ This research was sponsored by DFG within the "Schwerpunktprogramm Deduktion".
doi:10.1007/3-540-58156-1_57 fatcat:wpnsodwck5eohicbkaabbd2nnq