Opened 9 years ago

Last modified 4 years ago

#9391 new defect

kolyvagin_cohomology_class() method differs from doc

Reported by: justin Owned by: cremona
Priority: major Milestone:
Component: elliptic curves Keywords: kolyvagin classes
Cc: Merged in:
Authors: Justin Walker Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description (last modified by chapoton)

If P is a 'kolyvagin_point' created from an elliptic curve, the doc string says

Definition: P.kolyvagin_cohomology_class(self, n=None)
Docstring:
       INPUT:
    
          * n -- positive integer that divides the gcd of a_p and p+1 for
            all p dividing the conductor.  If n is None, choose the
            largest valid n.

In fact, if "n" is None, a ValueError? is thrown.

Change History (2)

comment:1 Changed 5 years ago by chapoton

The problem happens when the conductor is 1.

sage: y = EllipticCurve('389a').heegner_point(-7,1)
sage: y.conductor()
1
sage: P=y.kolyvagin_cohomology_class()
BOOM

This is because the gcd of the empty list is 0. I do not know what to do to solve the issue.

comment:2 Changed 4 years ago by chapoton

  • Description modified (diff)
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