#12630: Add representations of quivers and quiver algebras to sage
-------------------------------------------+--------------------------------
       Reporter:  JStarx                   |         Owner:  AlexGhitza  
           Type:  enhancement              |        Status:  needs_review
       Priority:  major                    |     Milestone:  sage-5.10   
      Component:  algebra                  |    Resolution:              
       Keywords:  algebra, quiver, module  |   Work issues:              
Report Upstream:  N/A                      |     Reviewers:              
        Authors:  Jim Stark                |     Merged in:              
   Dependencies:  #12412, #12413           |      Stopgaps:              
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Comment (by SimonKing):

 From the documentation of the patch:
 {{{
         9       A Quiver is a directed graph used for representation
 theory.  In Sage a Quiver
         10      is different from a directed graph in the following ways:
         11
         12      - The vertices of a DiGraph are arbitrary sage objects,
 but the vertices of a
         13        Quiver must be labeled by integers.
         14
         15      - DiGraphs can have cycles (paths that start and end at
 the same vertex) and
         16        even loops (edges whose initial and terminal vertices
 are equal).  In this
         17        implementation a Quiver must be acyclic (and can not
 have loops).
         18
         19      - The edges of a DiGraph are labeled with arbitrary sage
 objects or None if no
         20        label is specified.  Each edge of a Quiver must be
 labeled with a nonempty
         21        string.  The label cannot begin with 'e_' or contain '*'
 and distinct edges
         22        must have distinct labels.
         23
         24      - DiGraphs do not have a unique representation in Sage;
 Quivers do.
 }}}
 All these properties could easily be enforced by using a `UniqueFactory`
 that returns plain immutable digraphs. Given the above specification, I
 really don't see the need to create `Quiver_generic` as a sub-class of
 `DiGraph`.

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12630#comment:32>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
and MATLAB

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