Ticket #6406 (closed defect: fixed)

Opened 9 months ago

Last modified 8 months ago

[with patch, with positive review] fixing p_primary_bound on Tate-Shafarevich groups not to allow the reducible case

Reported by: wuthrich Owned by: was
Priority: minor Milestone: sage-4.1
Component: number theory Keywords: elliptic curves, tate shafarevich group,
Cc: rlm Author(s): Chris Wuthrich
Report Upstream: Reviewer(s): John Cremona
Merged in: sage-4.1.alpha3 Work issues:

Description

Currently the p_primary_bound pretends to give back a proven result when the p-torsion is reducible. That is wrong.

Attachments

trac_6406.patch Download (2.7 KB) - added by wuthrich 9 months ago.

Change History

Changed 9 months ago by wuthrich

Changed 9 months ago by wuthrich

  • cc rlm added
  • summary changed from fixing p_primary_bound on Tate-Shafarevich groups not to allow the reducible case to [with patch, needs review] fixing p_primary_bound on Tate-Shafarevich groups not to allow the reducible case
  • milestone set to sage-4.1

.... and there was a bug. It actually never tested for surjectivity, since {{not E.is_surjective(p)}} is always False.

Changed 9 months ago by cremona

  • reviewer set to John Cremona
  • summary changed from [with patch, needs review] fixing p_primary_bound on Tate-Shafarevich groups not to allow the reducible case to [with patch, with positive review] fixing p_primary_bound on Tate-Shafarevich groups not to allow the reducible case
  • author set to Chris Wuthrich

Looks good, applies fine to 4.1.alpha2 and tests pass (I tested all schemes/elliptic_curves).

Is it possible to add a doctest illustrating the suggestion to "try an_padic instead"? That would be useful for the reference manual. Of course, an_padic has its own tests but it would look good to include one right after one of the new tests which shows the message.

Changed 8 months ago by rlm

  • status changed from new to closed
  • resolution set to fixed
  • merged set to sage-4.1.alpha3
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