Twee is an experimental equational theorem prover based on Knuth-Bendix completion. Given a set of equational axioms and a set of equational conjectures it will try to prove the conjectures. It will terminate if the conjectures are true but normally fail to terminate if they are false. The input problem should be in TPTP format (see http://www.tptp.org). You can use types and quantifiers, but apart from that the problem must be equational.