#19397: Add support for homogeneous components of a filtered module
-------------------------------------+-------------------------------------
       Reporter:  tscrim             |        Owner:  sage-combinat
           Type:  enhancement        |       Status:  needs_review
       Priority:  major              |    Milestone:  sage-6.10
      Component:  categories         |   Resolution:
       Keywords:                     |    Merged in:
        Authors:  Travis Scrimshaw   |    Reviewers:
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  public/categories/homogeneous_components-19397|  
ae81aa7c64064ba8de5598aa01210efac57088c9
   Dependencies:  #17096             |     Stopgaps:
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Comment (by jhpalmieri):

 One mathematical issue: in defining `homogeneous_component`, you have
 {{{
 category = ModulesWithBasis(self.category().base_ring())
 }}}
 A homogeneous component of an ''R''-module need not be an ''R''-module
 itself in a natural way: for example, if the base ring is the graded ring
 ''R''=''k''[''x'', ''x''^-1^] with ''x'' in some nonzero degree, then for
 any homogeneous component of any graded ''R''-module, ''x'' would have to
 act trivially (because ''x'' has nonzero degree). On the other hand, ''x''
 is supposed to be invertible.

 It will always be a module over the degree 0 part of the base ring,
 though.

--
Ticket URL: <http://trac.sagemath.org/ticket/19397#comment:7>
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