Ticket #12880 (new defect)

Opened 14 months ago

Inconsistent domain, codomain and parent in EllipticCurveIsogeny

Reported by: nthiery Owned by: was
Priority: major Milestone: sage-5.11
Component: number theory Keywords:
Cc: sage-combinat Work issues:
Report Upstream: N/A Reviewers:
Authors: Merged in:
Dependencies: Stopgaps:

Description

In the following example, the domain and codomain of phi does not match with that of its parent::

    sage: sage: E = EllipticCurve(j=GF(7)(0))
    sage: phi = EllipticCurveIsogeny(E, [E(0), E((0,1)), E((0,-1))])
    sage: phi.parent()
    Set of Morphisms from Abelian group of points on Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7 to Abelian group of points on Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7 in Category of hom sets in Category of Schemes
    sage: phi.parent().domain()
    Abelian group of points on Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7
    sage: phi.domain()
    Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7
    sage: phi.parent().codomain()
    Abelian group of points on Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7
    sage: phi.codomain()
    Elliptic Curve defined by y^2 = x^3 + 1 over Finite Field of size 7
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