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(GF(2),6,order='invlex') I = R.ideal([ mynumerator((uy1^2+ux1*uy1)-(ux1^3+ua2*ux1^2+ua6)) , mynumerator((uy2^2+ux2*uy2)-(ux2^3+ua2*ux2^2+ua6)) ]) J = I + R.ideal([0 , ux1-ux2 , uy1-uy2 ]) ua2 = fastfrac(ua2) ua6 = fastfrac(ua6) ux1 = fastfrac(ux1) uy1 = fastfrac(uy1) ux2 = fastfrac(ux2) uy2 = fastfrac(uy2) ux3 = ((((uy1+uy2)/(ux1+ux2))^2+((uy1+uy2)/(ux1+ux2))+ux1+ux2+ua2)).reduce() uy3 = ((((uy1+uy2)/(ux1+ux2))^3+(ux2+ua2+fastfrac(1))*((uy1+uy2)/(ux1+ux2))+ux1+ux2+ua2+uy1)).reduce() ux4 = (((ux1+uy1/ux1)^2+(ux1+uy1/ux1)+ua2)).reduce() uy4 = (((ux1+uy1/ux1)^3+(ux1+ua2+fastfrac(1))*(ux1+uy1/ux1)+ua2+uy1)).reduce() a0 = fastfrac((fastfrac(1))) a1 = fastfrac((fastfrac(1))) a2 = fastfrac((ua2)) a3 = fastfrac((fastfrac(0))) a4 = fastfrac((fastfrac(0))) a6 = fastfrac((ua6)) wweierx1 = ((ux1)).reduce().sreduce() wweiery1 = ((uy1)).reduce().sreduce() print isidentity(a0*(wweiery1^2)+a1*(wweierx1*wweiery1)+a3*wweiery1-(((wweierx1+a2)*wweierx1+a4)*wweierx1+a6)) print isidentity(ux1-(wweierx1)) print isidentity(uy1-(wweiery1)) wweierx2 = ((ux2)).reduce().sreduce() wweiery2 = ((uy2)).reduce().sreduce() wweierx3 = ((ux3)).reduce().sreduce() wweiery3 = ((uy3)).reduce().sreduce() wweierx4 = ((ux4)).reduce().sreduce() wweiery4 = ((uy4)).reduce().sreduce() slope = ((wweiery2-wweiery1)/(wweierx2-wweierx1)).reduce().sreduce() print isidentity(a0*slope^2+a1*slope-a2-wweierx1-wweierx2-wweierx3) print isidentity(slope*(wweierx1-wweierx3)-wweiery1-a1*wweierx3-a3-wweiery3) slope = ((fastfrac(3)*wweierx1^2+fastfrac(2)*a2*wweierx1+a4-a1*wweiery1)/(fastfrac(2)*a0*wweiery1+a1*wweierx1+a3)).reduce().sreduce() print isidentity(a0*slope^2+a1*slope-a2-wweierx1-wweierx1-wweierx4) print isidentity(slope*(wweierx1-wweierx4)-wweiery1-a1*wweierx4-a3-wweiery4)