Removing assignment at the top-level



> (%i16)  z : 9 - sqrt(z)^2;
> (%o16)                               9 - z
> (%i17)  z : 9 - (z)^2;
>                                             2
> (%o17)                           9 - (9 - z)
> (%i18)  z : 9 - z^2;
>                                               2 2
> (%o18)                        9 - (9 - (9 - z) )
> (%i19)  z : (9 - z)^2;
>                                             2 4
> (%o19)                          (9 - (9 - z) )
> (%i20) z : 0$
> (%i21) z;
> (%o21)                                 0
> (%i22)  z : 9 - z^2;
> (%o22)                                 9
> (%i23)  z := 9 - z^2;
> 
>  I couldn't find in the documentation. Perhaps I need to sleep?
>  How do I "forget"?

kill(z);

-- 
Mario Rodriguez Riotorto
www.biomates.net