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,6,order='invlex') I = R.ideal([ mynumerator((uy1^2)-(ux1^4+2*ua*ux1^2+1)) , mynumerator((ux1)-(uX1/uZ1)) , mynumerator((uy1)-(uY1/uZ1^2)) ]) ua = fastfrac(ua) ux1 = fastfrac(ux1) uy1 = fastfrac(uy1) uX1 = fastfrac(uX1) uY1 = fastfrac(uY1) uZ1 = fastfrac(uZ1) uX3 = ((uX1*uZ1*uY1+uY1*uX1*uZ1)) uY3 = ((((uZ1*uZ1)^2+(uX1*uX1)^2)*(uY1*uY1+fastfrac(2)*ua*uX1*uX1*uZ1*uZ1)+fastfrac(2)*uX1*uX1*uZ1*uZ1*(uX1^2*uZ1^2+uZ1^2*uX1^2))) uZ3 = (((uZ1*uZ1)^2-(uX1*uX1)^2)) ux3 = (((ux1*uy1+uy1*ux1)/(fastfrac(1)-(ux1*ux1)^2))).reduce() uy3 = ((((fastfrac(1)+(ux1*ux1)^2)*(uy1*uy1+fastfrac(2)*ua*ux1*ux1)+fastfrac(2)*ux1*ux1*(ux1^2+ux1^2))/(fastfrac(1)-(ux1*ux1)^2)^2)).reduce() print isidentity((uy3^2)-(ux3^4+fastfrac(2)*ua*ux3^2+fastfrac(1))) print isidentity((ux3)-(uX3/uZ3)) print isidentity((uy3)-(uY3/uZ3^2))