Hi Niles and Koffie! On 2 Aug., 12:26, Niles <[email protected]> wrote: > ... > (Also, I have checked the example given in the docstring for elliptic > curve 14a, and the power series patch does not affect this answer. In > fact the patch passes all tests from 'make ptestlong' except for the > one mentioned in this bug)
By inserting some print statements in the code for comparing power series, I found that during computation of lp.Dp_valued_series(4,quadratic_twist=D, prec=4) there is one comparison of O(T^4) with zero, where T is generator of a power series ring over some p-adics. The patch changes this comparison. Without patch: sage: R.<T>=ZZ.completion(5,5)[[]] sage: O(T^4)==0 False but with the patch, O(T^4)==0 is true. So, it is not surprising that the patch changes the result of the lp.Dp_valued_series(4,quadratic_twist=D, prec=4). However, the question is whether the old result was correct. After all, if I am not mistaken, O(T^4) *should* evaluate to zero. I think this is why Niles and I are asking on this list: Can some expert on elliptic curves please verify whether the old result of lp.Dp_valued_series(4,quadratic_twist=D, prec=4) was correct? We have some doubts (since the comparison O(T^4)!=0 seems wrong to us), but since I know virtually nothing about elliptic curves, I wouldn't be able to verify the result. Cheers, Simon -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
