#16949: Improve gens() for elliptic curves over a finite field
-------------------------------------+-------------------------------------
       Reporter:  jdemeyer           |        Owner:
           Type:  enhancement        |       Status:  needs_review
       Priority:  major              |    Milestone:  sage-6.10
      Component:  elliptic curves    |   Resolution:
       Keywords:                     |    Merged in:
        Authors:  Jeroen Demeyer     |    Reviewers:
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  u/jdemeyer/improve_abelian_group___for_elliptic_curves_over_a_finite_field|  
46393f34e5bf179dfc79a4fa597838ef18910981
   Dependencies:                     |     Stopgaps:
-------------------------------------+-------------------------------------

Comment (by cremona):

 I will trust you that there are cases where this is all that the users
 needs.

 Can we add to the documentation more from the documentation of pari's
 ellgroup() function?  As I understand that, if ellgroup()[2] has length 1
 then the group is cyclic and this point does generate it;  while if it has
 length 2 then the first point has order d1 = exponent, the structure is
 [d1,d2] with d2>1 and d1|d1, and the Weil pairing between the points has
 order exactly d2 even though the second "generator" may have order not d2
 (its order must then be a multiple of d2 and a divisor of d1).

 As the pari doc says, this avoids the possibly expensive Weil pairing
 step.

 I will be testing this shortly.

--
Ticket URL: <http://trac.sagemath.org/ticket/16949#comment:5>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
and MATLAB

-- 
You received this message because you are subscribed to the Google Groups 
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.

Reply via email to