Opened 15 years ago

Closed 14 years ago

Last modified 14 years ago

#2358 closed defect (worksforme)

phi(I) for phi a ring morphism and I an ideal should work (IMHO); it used to and now it doesn't because of new-ish arithmetic architecture stuff

Reported by: William Stein Owned by: somebody
Priority: major Milestone: sage-3.3
Component: basic arithmetic Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

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Who rewrote the ring morphism code so that if phi is a
ring morphism, then phi(I) no longer works, for an ideal I?
Oh, David Roed in changeset 6772 (for me) from a few
months ago did this:

  "Cython'ed sage/rings/, actually added wrapper_parent (even though I claimed to in the previous commit)."

I think that feature, i.e., that phi(I) works, was very nice
and is standard notation in mathematics, and I want
it back.   Then the codepath that leads to the above weird
bug wouldn't exist.

I think the way to fix this is:
  (1) Rethink the assumption you're forcing on morphisms that they
can only apply to elements in the domain.   This overloading of
calling a morphism on (sub)objects is very standard in mathematics.
  (2) Change the architecture of __call__ as a result of (1).

 -- William

Change History (2)

comment:1 Changed 14 years ago by David Roe

Resolution: worksforme
Status: newclosed

This was previously fixed. See

comment:2 Changed 14 years ago by Michael Abshoff

Milestone: sage-3.4.1sage-3.3
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