Dear sage-support, I was playing with some elliptic-curves calculations in Sage 4.5.3, and I came across (or, rather, cooked up) the following, which puzzled me:
sage: K = QuadraticField(8,'a') sage: E = EllipticCurve([K(0),0,0,-1,0]) sage: P = E([-1,0]) sage: P.division_points(2) [] sage: P.is_divisible_by(2) True Is this the intended behavior? From the source code, it looks as if P.is_divisible_by(2) just checks whether the x-coordinate of the system of equations for dividing P by 2 can be solved over K. The division_points method does the full check of whether the system has a solution over K. Shouldn't is_divisible_by do the same thing? Thanks for any clarification you can offer. Regards, James Parson -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
