System of two polynomial equations

[ewan.Delanoy@math.unicaen.fr]

             Hello all,

     if F and G are two polynomials in two variables x
and y, the system {F(x,y)=0,G(x,y)=0}, is usually
equivalent to a system of the form {P(x)=0,y=Q(x)}, where
P and Q are univariate polynomials.

  P can be easily computed with GP: it's essentially equal to
polresultant(F(x,y),G(x,y),y).
   What about Q ? I can't think of a GP function that deals with
this in a simple way.

             Thanks in advance for any help,

                               Ewan