On Wed, 21 Dec 2011, Burcin Erocal wrote:
> There is also Sage:
>
> http://sagemath.org/
>
> It's far from a "toy" or a specialized system (such as pari/gp,
> Singular, Macaulay2, etc.). So it should be mentioned.
Of course, it's not a toy. To a large degree, it's a large collection of 
existing software, "Gentoo of maths", with its own package system. And it 
includes maxima, fricas, pari/gp, gap, singular, R, and many other 
systems. They are all integrated together to some degree, so, sage is 
somewhere in between a monolythic CAS (maxima, reduce, fricas,...) and 
just a collection.

It would be interesting to make reduce one of its packages, too.

Andrey