#9972: Add toric lattice morphisms
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Reporter: novoselt | Owner: mhampton
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-4.6
Component: geometry | Keywords:
Author: Andrey Novoseltsev | Upstream: N/A
Reviewer: Volker Braun | Merged:
Work_issues: switch to FanMorphism |
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Comment(by novoselt):
What membership exactly do you want to test?
The assumption is that there are no invalid cones of the fan, so if you
want
to check if a cone is in the fan, it is enough to check if the ambient fan
of the cone is the fan in question. For checking equivalence of two cones
of the same fan it is enough indeed to check that their ambient ray
indices are the same, as tuples, since they are always assumed to be
sorted and when they are not - it is a bug.
I don't mind adding uniqueness of cones of fan or even cones themselves
for that matter (on a separate ticket, perhaps?), I just don't quite
understand why do you want it. The advantages that I see are
* memory saving;
* cached data sharing;
and disadvantages
* more complicated code for construction;
* longer time for construction.
Do you have something else in mind?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9972#comment:14>
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