Function: qfbcomp
Section: number_theoretical
C-Name: qfbcomp
Prototype: GG
Help: qfbcomp(x,y): Gaussian composition with reduction of the binary
 quadratic forms x and y.
Doc: \idx{composition} of the binary quadratic forms $x$ and $y$, with
 \idx{reduction} of the result.
 \bprog
 ? x=Qfb(2,3,-10);y=Qfb(5,3,-4);
 ? qfbcomp(x,y)
 %2 = Qfb(-2, 9, 1)
 ? qfbcomp(x,y)==qfbred(qfbcompraw(x,y))
 %3 = 1
 @eprog
