The Coq proof assistant
- Allows the user to handle calculus assertions, to check mechanically proofs of these assertions, helps to find formal proofs, extracts a certified program from the constructive proof of its formal specification.
- http://coq.inria.fr/
CtCoq - a working environment for the Coq theorem prover (XWindow) - http://www-sop.inria.fr/croap/ctcoq/ctcoq-eng.html