def mynumerator(x): if parent(x) == R: return x return numerator(x) class fastfrac: def __init__(self,top,bot=1): if parent(top) == ZZ or parent(top) == R: self.top = R(top) self.bot = R(bot) elif top.__class__ == fastfrac: self.top = top.top self.bot = top.bot * bot else: self.top = R(numerator(top)) self.bot = R(denominator(top)) * bot def reduce(self): return fastfrac(self.top / self.bot) def sreduce(self): return fastfrac(I.reduce(self.top),I.reduce(self.bot)) def iszero(self): return self.top in I and not (self.bot in I) def isdoublingzero(self): return self.top in J and not (self.bot in J) def __add__(self,other): if parent(other) == ZZ: return fastfrac(self.top + self.bot * other,self.bot) if other.__class__ == fastfrac: return fastfrac(self.top * other.bot + self.bot * other.top,self.bot * other.bot) return NotImplemented def __sub__(self,other): if parent(other) == ZZ: return fastfrac(self.top - self.bot * other,self.bot) if other.__class__ == fastfrac: return fastfrac(self.top * other.bot - self.bot * other.top,self.bot * other.bot) return NotImplemented def __neg__(self): return fastfrac(-self.top,self.bot) def __mul__(self,other): if parent(other) == ZZ: return fastfrac(self.top * other,self.bot) if other.__class__ == fastfrac: return fastfrac(self.top * other.top,self.bot * other.bot) return NotImplemented def __rmul__(self,other): return self.__mul__(other) def __div__(self,other): if parent(other) == ZZ: return fastfrac(self.top,self.bot * other) if other.__class__ == fastfrac: return fastfrac(self.top * other.bot,self.bot * other.top) return NotImplemented def __pow__(self,other): if parent(other) == ZZ: return fastfrac(self.top ^ other,self.bot ^ other) return NotImplemented def isidentity(x): return x.iszero() def isdoublingidentity(x): return x.isdoublingzero() R. = PolynomialRing(QQ,7,order='invlex') I = R.ideal([ mynumerator((ux1^2+uy1^2)-(uc^2*(1+ud*ux1^2*uy1^2))) , mynumerator((ur*uy1^2)-(uY1/uZ1)) , mynumerator((uc)-(1)) , mynumerator((ud)-(ur^2)) ]) uc = fastfrac(uc) ud = fastfrac(ud) ur = fastfrac(ur) ux1 = fastfrac(ux1) uy1 = fastfrac(uy1) uY1 = fastfrac(uY1) uZ1 = fastfrac(uZ1) uY3 = ((uY1/uZ1)) uZ3 = ((fastfrac(1))) ux3 = ux1 uy3 = uy1 print isidentity((ux3^2+uy3^2)-(uc^2*(fastfrac(1)+ud*ux3^2*uy3^2))) print isidentity((ur*uy3^2)-(uY3/uZ3))