Sage: Open Source Mathematics Software
Released 1.1 Version 1.1 was just released. It includes an editor for relations, removing the need to edit them externally.Also now uses regular expressions to forbid invalid attribute names and gives to the user more feedback on incorrect relations. For now windows and mac versions are not available, but the introduced support to PySide should make it easier on Mac to install the dependencies. For the developers, the API has been changed and now accepts unicode objects instead of utf-8 encoded strings. start [Relational Algebra]
Axiom Computer Algebra System Axiom is a general purpose Computer Algebra system. It is useful for research and development of mathematical algorithms. It defines a strongly typed, mathematically correct type hierarchy. It has a programming language and a built-in compiler. Axiom has been in development since 1971. At that time, it was called Scratchpad.
GAP System for Computational Discrete Algebra Welcome to GAP - Groups, Algorithms, Programming - a System for Computational Discrete Algebra The current version is GAP 4.7.4 released on 20 February 2014.