Franz Lehner

Varia

Computer Algebra

Since MuPAD went commercial I use Axiom in combination with Aldor for computations. Actually, the most useful fork of Axiom at the moment (and perhaps for the next 30 years) is FriCAS ; but see also OpenAxiom.
For group related things GAP is the most powerful package available. All these run on Debian GNU/Linux systems.
To be continued ...