-----maxima-bounces at math.utexas.edu wrote: -----
<< Checking even correct solutions is sometimes not possible,
The to_poly_solver tries to convert an equation into an equivalent
polynomial equation along with inequalities that a solution must
satisfy: example
(%i3) to_poly(sqrt(x)=a,[x]);
(%o3) [[%g338-a,x=%g338^2],[-%pi/2<parg(%g338),parg(%g338)<=%pi/2],[]]
The constraints [-%pi/2<parg(%g338),parg(%g338)<=%pi/2] stipulate that
%g338 (aka 'a') is in the range of the square root.
Presumably, the constraint(s) are easier to check than are the solutions.
--Barton