I don't know about the others and their dependencies, but Pari/GP is just a binary executable. If you can copy files into your Zaurus (eg using ssh/scp or with a memory card), just copy the file to somewhere in your PATH (eg /usr/bin/ ) and make it executable (chmod a+x). You might need to be root to do that. Then, if the file is called gp, just typing gp at the command prompt will launch it.
Felipe