Engineering mathematics: the odd order theorem proof

Even with the assistance of computer tools, the formalized de-scription and verification of research-level mathematics remains a daunting task, not least because of the talent with which mathema-ticians combine diverse theories to achieve their ends. By combin-ing tools and techniques from type theory, language design, and software engineering we have managed to capture enough of these practices to formalize the proof of the Odd Order theorem, a landmark result in Group Theory.