Opened 13 years ago

Closed 13 years ago

#6406 closed defect (fixed)

[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 Merged in: sage-4.1.alpha3
Authors: Chris Wuthrich Reviewers: John Cremona
Report Upstream: Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Description

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

Attachments (1)

trac_6406.patch (2.7 KB) - added by wuthrich 13 years ago.

Download all attachments as: .zip

Change History (4)

Changed 13 years ago by wuthrich

comment:1 Changed 13 years ago by wuthrich

  • Cc rlm added
  • Milestone set to sage-4.1
  • 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

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

comment:2 Changed 13 years ago by cremona

  • Authors set to Chris Wuthrich
  • Reviewers 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

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.

comment:3 Changed 13 years ago by rlm

  • Merged in set to sage-4.1.alpha3
  • Resolution set to fixed
  • Status changed from new to closed
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