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,10,order='invlex') I = R.ideal([ mynumerator((ua*ux1^3+uy1^3+1)-(ud*ux1*uy1)) , mynumerator((ux1)-(uX1/uZ1)) , mynumerator((uy1)-(uY1/uZ1)) , mynumerator((ui^2)-(-1)) , mynumerator((uminustwo)-(-2)) , mynumerator((u2d)-(2*ud)) ]) uminustwo = fastfrac(uminustwo) ui = fastfrac(ui) ua = fastfrac(ua) u2d = fastfrac(u2d) ud = fastfrac(ud) ux1 = fastfrac(ux1) uy1 = fastfrac(uy1) uX1 = fastfrac(uX1) uY1 = fastfrac(uY1) uZ1 = fastfrac(uZ1) uiZ = ((ui*uZ1)) uA = (((uY1-uiZ)*(uY1+uiZ))) uB = ((uY1*uZ1)) uC = (((uA-uB)*(uY1+uZ1))) uD = (((uA+uB)*(uZ1-uY1))) uE = ((fastfrac(3)*uC-u2d*uX1*uB)) uX3 = ((uminustwo*uX1*uD)) uY3 = (((uD-uE)*uZ1)) uZ3 = (((uD+uE)*uY1)) ux3 = (((ux1-uy1^3*ux1)/(ua*uy1*ux1^3-uy1))).reduce() uy3 = (((uy1^3-ua*ux1^3)/(ua*uy1*ux1^3-uy1))).reduce() print isidentity((ua*ux3^3+uy3^3+fastfrac(1))-(ud*ux3*uy3)) print isidentity((ux3)-(uX3/uZ3)) print isidentity((uy3)-(uY3/uZ3))