o = [Mod(0,3),y,1/y, (y^2+1)/y, [1,2,3], Vecsmall([1,2,0]), Qfb(1,2,4), Qfb(1,2,-4), y+2*y^2+O(y^4)];
{
  for (i=1,#o,
    my (v = o[i]);
    printsep(" ", Pol(v,y), Pol(v,x), Polrev(v));
    printsep(" ", Ser(v,y), Ser(v,x), Ser(v,,5));
  )
}
o = [2*x+3*y, 2+x+y+O(x^2), 2+x+y+O(y^2)];
{
  for (i=1,#o,
    my (v = o[i]);
    printsep(" ",pollead(v), pollead(v,x), pollead(v,y))
  )
}
polgraeffe(x^2+x+1)
polgraeffe(x^3+x+1)
polsym(2*x^4+1,4)
norm(I*x+1)
trace(I*x+1)
matcompanion(2*x^2+1)
Pol("")

\\#1651
f1=(x-1)/(x*x-x);
type(subst(1/f1,x,1))

\\#1690
default(realprecision,38);
P(x,y)=(x+1)*y^2+(x^2-x+1)*y+(x^2+x);
polroots(P(exp(I*Pi),y))
