#12892: Toric fibration morphisms
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Reporter: vbraun | Owner: AlexGhitza
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.3
Component: algebraic geometry | Resolution:
Keywords: sd40.5 | Work issues: comments and rebasing
Report Upstream: N/A | Reviewers: Andrey Novoseltsev
Authors: Volker Braun | Merged in:
Dependencies: #12361, #13023 | Stopgaps:
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Comment (by novoselt):
Thinking some more about the last example (which I think we should support
for sure): am I right that the image is a toric variety, but not normal,
so there is no fan corresponding to it? As I just checked,
`restrict_to_image` so far is a method of fan morphisms only and using it
here does nothing. I think this has to be the case, but the documentation
should be clarified as the restriction does not have to be surjective. It
kind of contradicts the name though, should we rename it? I think it is
`restrict_to_image_closure` inside of the codomain. We can rename the
current method to it and then have `restrict_to_image` which will do the
same, but then check that the result is surjective and `raise ValueError`
otherwise since "proper image restriction" is no longer a fan morphism.
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12892#comment:21>
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