Software verification tool

 Why aims at being a verification conditions generator (VCG) back-end
 for other verification tools. It provides a powerful input language
 including higher-order functions, polymorphism, references, arrays and
 exceptions. It generates proof obligations for many systems: the proof
 assistants Coq, PVS, Isabelle/HOL, HOL 4, HOL Light, Mizar and the
 decision procedures Simplify, Alt-Ergo, Yices, CVC Lite and haRVey.