General purpose computer algebra system released under GPLv3. French
documentation by Renee De Graeve is for non-commercial use only. The
package consists of:

 - C++ library (libgiac). It is build on C and C++ libraries: PARI,
   NTL (arithmetic), CoCoA (Groebner basis), GSL (numerics), GMP
   (big integers), MPFR (bigfloats) and provides algorithms for basic
   polynomial operations (product, GCD) and symbolic computations
   (simplifications, limits/series, symbolic integration, summation,
   ...). The library can be configured to accept Maple or TI syntax
   to ease the transition for users of these systems.
 - Command line interpreter (icas or giac). It can be called from
   texmacs.
 - FLTK-based GUI (xcas). It is a GUI for symbolic computation with
   several modules added: 2-d and 3-d graphics, dynamic 2-d and 3-d
   geometry (exact or numeric), spreadsheet, programming environment.

WWW: http://www-fourier.ujf-grenoble.fr/~parisse/giac.html