This Python library for symbolic mathematics is a fork of the SymPy, started by Sergey B Kirpichev, last regular SymPy's commit is cbdd072 (22 Feb 2015). The git history goes back to 2007.
The project was named after the Diophantus of Alexandria. His "Arithmetica" is one of the earliest known texts that use symbols in equations. "Diofant" is a transliteration of Диофант, from Russian.
Unless stated otherwise, all files in the Diofant project are licensed using the new BSD license: