#12630: Add representations of quivers and quiver algebras to sage
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Reporter: JStarx |
Owner: AlexGhitza
Type: enhancement |
Status: needs_work
Priority: major |
Milestone: sage-5.11
Component: algebra |
Resolution:
Keywords: algebra, quiver, module, days49 |
Work issues: Use existing infrastructure for Homspase and Morphism.
Report Upstream: N/A |
Reviewers:
Authors: Jim Stark, Simon King, Mathieu Guay-Paquet, Aladin Virmaux |
Merged in:
Dependencies: #12412, #12413 |
Stopgaps:
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Comment (by SimonKing):
It may be that the last remaining doctest is just a problem with _repr_.
However, the returned representation really looks fishy, it looks like the
quiver involved is broken. So, let's investigate what is happening.
Note that I think the following test should be rewritten anyway. The
morphism f should be constructed via `f = P2.hom({1:[1, 1], 2:[[1], [1]]},
M2)` or so, since this is generally the preferred way of creating a
morphism. Importing and directly calling a class that has a "mutilated"
name (`QuiverRepHom`) is not what the user is supposed to do. The simple
reason is that the user would first need to learn where to import it from.
But `hom` is a method that the user has very likely seen before in Sage.
{{{
sage: Q2 = Quiver({1:{2:['a', 'b']}})
sage: M2 = QuiverRep(QQ, Q2, {1: QQ^2, 2: QQ^1}, {(1, 2, 'a'): [1, 0],
(1, 2, 'b'): [0, 1]})
sage: P2 = Q2.P(QQ, 1)
sage: from sage.quivers.morphism import QuiverRepHom
sage: f = QuiverRepHom(P2, M2, {1:[1, 1], 2:[[1], [1]]})
sage: f.linear_dual()
Expect:
Homomorphism of representations of Quiver on 2 vertices
Got:
Homomorphism of representations of Quiver on Reverse of ()
}}}
The underlying problem seems to be this:
{{{
sage: Q2.reverse()
Quiver on Reverse of ()
}}}
So, let's have a look at the `reverse()` method.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12630#comment:80>
Sage <http://www.sagemath.org>
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