#10527: Implementation of quiver mutation type
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Reporter: stumpc5 | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.3
Component: combinatorics | Resolution:
Keywords: quiver mutation type days38 | Work issues:
Report Upstream: N/A | Reviewers: Hugh Thomas
Authors: Christian Stump | Merged in:
Dependencies: | Stopgaps:
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Comment (by hthomas):
Gregg, I'm not sure I understand what you're trying to do with the code
for the non-simply-laced elliptics.
It seems to me that the code constructing the digraph for F,4,[2,1] is
never called, because that input is automatically recast as F,4,[1,2]
before that point in the code is reached.
But if that code were run, I think it would cause problems. As it stands,
we have a quiver mutation type called F,4,[1,2]. It has certain
attributes, including a digraph. If you could ask for F,4,[2,1] and get a
mutation type that was also called F,4,[1,2] but which had a different
digraph, I think that would be really confusing (and I think it would
screw up the cached methods, too).
It is certainly natural for users to ask for a specific quiver. But if
someone really wants to ask for a specific quiver, I don't think the right
mechanism for them to do it is for them to ask for a !QuiverMutationType
by a synonym. They should just ask for the quiver they want, and get that
quiver (as an actual quiver, not as a mutation type). And then, depending
on the implementation, we either figure out right then or later what the
mutation type of the quiver is that they asked for. I think we should
think of !QuiverMutationType(X) as just giving you a default quiver, on
the assumption that the user hasn't really specified a particular quiver.
This is also my real issue with the synonyms you added.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10527#comment:118>
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