FriCAS is a fork of Axiom.

FriCAS algebra library is written in a high level strongly typed
language (Spad), which allows natural expression of mathematical
algorithms.

FriCAS uses lightweight developement methodology.  Compared to Axiom
FriCAS is significantly restructured -- it is more portable and fixed
several defects.  FriCAS removed rather large unused parts (without
removing functionality).  It is expected that FriCAS will be much
easier to maintain than original Axiom.