Dear colleagues. I am developing category theory software. It includes objects, morphisms, diagrams, functors, direct and inverse limits. Software math categories include vector spaces, modules over fuclidean rings, finite sets, finitely generated commutative algebras. The software works with algebraic fields, complex and real field, Galois fields. The software supports following functors: Tensor products, Hom, Ext, Tor. Additional software feature is Homology calculations. The software requires .NET 2.0 You can download sofware from http://sourceforge.net/projects/categorytheory . Recent instructions you can download from http://prdownloads.sourceforge.net/categorytheory/CategoryTheory-doc-0.9.zip... If you wish improvement of the sofware vizit its forum http://sourceforge.net/forum/?group_id=160444 Yours sincerely Petr.