#14476: non-integral models can cause a bug in local_data for elliptic curves
over
number fields
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Reporter: wuthrich | Owner: cremona
Type: defect | Status: new
Priority: major | Milestone: sage-5.10
Component: elliptic curves | Resolution:
Keywords: local_data | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by wuthrich):
Just so that I don't forget what I found out so far :
The issue, as silly as it sounds, comes up from {{{__repr__}}} this class.
This does not display {{{_Emin}}} the minimal equation that Tate's
algorithm found, instead it wants to compute {{{minimal_model}}}. This
does nothing but calling {{{_reduced_model}}} in
{{{ell_number_fields.py}}}. And that is global again. So in
{{{_reduce_model}}} it checks if the coefficients are integers, while we
only need that they are local integers here.
The quick solution I see is to add to the local class a function to reduce
the model locally. But I will have to check what that is going to break.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14476#comment:3>
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