#8989: Add support for Fano toric varieties
----------------------------------+-----------------------------------------
Reporter: novoselt | Owner: AlexGhitza
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.5
Component: algebraic geometry | Keywords:
Author: Andrey Novoseltsev | Upstream: N/A
Reviewer: Volker Braun | Merged:
Work_issues: |
----------------------------------+-----------------------------------------
Changes (by novoselt):
* status: needs_work => needs_review
Comment:
OK, here are the changes:
* Toric variety `X` is now associated to the normal fan of `Delta`.
* Respectively, "old" `delta` was changed to `Delta_polar`.
* The class takes as input and stores inside `Delta_polar`, since that's
what is most relevant.
* The factory function accepts either `Delta` or `Delta_polar` (without
explicit clarification it is `Delta`, which means that #9245 will break a
little bit, the fix is to put `Delta_polar=polytope` on line 180).
* `P_Delta` did not mean "polar to Delta", it is `\mathbb{P}_{\Delta}`,
so it remains the same, except that in the new version `Delta` refers to
the polytope in the `M` lattice. (I did not really mention any lattices in
the documentation, using normal/face fans to distinguish the relation of
`Delta` and `Delta_polar` to `X`.)
* `coordinate_indices` are renamed to `coordinate_name_indices` and have
several doctests explaining why there is probably no need to use this
parameter (not like I want to remove it, I just hope that usually the
defaults will work nicely).
* `coefficient_name_indices` are added to the hypersurface constructor,
it was kind of a bug that originally it was not there - the idea is to
treat creation of names in the same fashion everywhere. I even think that
my `normalize_names` function should replace the one in `Parent`, but the
relevant discussion on sage-devel died without responses, so for now it is
used in toric varieties only.
* `point_to_variable` is renamed to `coordinate_point_to_coordinate`,
despite of discussion above. While working on its documentation, I decided
that this is the most natural name given that there are
`coordinate_points` and this function takes an element from there and
transforms it into a coordinate. If you disagree with this argument and
still prefer `Delta_polar_point_to_coordinate`, I'll change it.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8989#comment:17>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
