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,5,order='invlex') I = R.ideal([ mynumerator((uy1^2)-(ux1^4+2*ua*ux1^2+1)) , mynumerator((uy2^2)-(ux2^4+2*ua*ux2^2+1)) ]) J = I + R.ideal([0 , ux1-ux2 , uy1-uy2 ]) ua = fastfrac(ua) ux1 = fastfrac(ux1) uy1 = fastfrac(uy1) ux2 = fastfrac(ux2) uy2 = fastfrac(uy2) ux3 = (((ux1*uy2+uy1*ux2)/(fastfrac(1)-(ux1*ux2)^2))).reduce() uy3 = ((((fastfrac(1)+(ux1*ux2)^2)*(uy1*uy2+fastfrac(2)*ua*ux1*ux2)+fastfrac(2)*ux1*ux2*(ux1^2+ux2^2))/(fastfrac(1)-(ux1*ux2)^2)^2)).reduce() ux4 = (((ux1*uy1+uy1*ux1)/(fastfrac(1)-(ux1*ux1)^2))).reduce() uy4 = ((((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() a0 = fastfrac((fastfrac(2))) a1 = fastfrac((fastfrac(0))) a2 = fastfrac((-fastfrac(2)*ua)) a3 = fastfrac((fastfrac(0))) a4 = fastfrac((ua^2-fastfrac(1))) a6 = fastfrac((fastfrac(0))) wu1 = ((ua+(uy1+fastfrac(1))/ux1^2)).reduce().sreduce() wv1 = (((ua+(uy1+fastfrac(1))/ux1^2)/ux1)).reduce().sreduce() print isidentity(a0*(wv1^2)+a1*(wu1*wv1)+a3*wv1-(((wu1+a2)*wu1+a4)*wu1+a6)) print isidentity(ux1-(wu1/wv1)) print isidentity(uy1-((wu1-ua)*(wu1/wv1)^2-fastfrac(1))) wu2 = ((ua+(uy2+fastfrac(1))/ux2^2)).reduce().sreduce() wv2 = (((ua+(uy2+fastfrac(1))/ux2^2)/ux2)).reduce().sreduce() wu3 = ((ua+(uy3+fastfrac(1))/ux3^2)).reduce().sreduce() wv3 = (((ua+(uy3+fastfrac(1))/ux3^2)/ux3)).reduce().sreduce() wu4 = ((ua+(uy4+fastfrac(1))/ux4^2)).reduce().sreduce() wv4 = (((ua+(uy4+fastfrac(1))/ux4^2)/ux4)).reduce().sreduce() slope = ((wv2-wv1)/(wu2-wu1)).reduce().sreduce() print isidentity(a0*slope^2+a1*slope-a2-wu1-wu2-wu3) print isidentity(slope*(wu1-wu3)-wv1-a1*wu3-a3-wv3) slope = ((fastfrac(3)*wu1^2+fastfrac(2)*a2*wu1+a4-a1*wv1)/(fastfrac(2)*a0*wv1+a1*wu1+a3)).reduce().sreduce() print isidentity(a0*slope^2+a1*slope-a2-wu1-wu1-wu4) print isidentity(slope*(wu1-wu4)-wv1-a1*wu4-a3-wv4)