Juha Arpiainen has implemented his own proof checker in Common Lisp called Bourbaki and Marnix Klooster has coded a proof checker in Haskell called Hmm.
Juha Arpiainen designed his own proof checker program written in Common Lisp named Bourbaki, and Marnix Klooster coded a proof checker program in Haskell called Hmm.