Package eprover-1.3-2

E is a purely equational theorem prover for full first-order logic. That means it is a program that you can stuff a mathematical specification (in first-order format) and a hypothesis into, and which will then run forever, using up all of your machines resources. Very occasionally it will find a proof for the hypothesis and tell you so... E's inference core is based on a modified version of the superposition calculus for equational clausal logic as described in [BG94]. For the case of pure unit equality (where both goals and axioms are simple equations, not disjunctions of literals or conditional rules), the calculus degenerates to unfailing completion [BDP89] extended to deal with arbitrarily quantified goals as implemented in DISCOUNT [DKS97]. Current versions offers a variety of literal selection functions and can e.g. emulate the unit-paramodulation strategy described in [Der91] for Horn clauses. E can now also handle full first-order logic. It uses a standard clausification algorithm to translate first order formula to clausal logic. Both clausification and reasoning on the clausal form can be documented in checkable proof objects. The prover was intended to become part of a METOP-based version of E-SETHEO [Mos96]. E-SETHEO now has evolved into a multi-paradigm strategy parallel proof system, but E is still a cornerstone of the system.