#16340: Infrastructure for modelling full subcategories
-------------------------------------+-------------------------------------
       Reporter:  nthiery            |        Owner:
           Type:  enhancement        |       Status:  needs_review
       Priority:  major              |    Milestone:  sage-6.4
      Component:  categories         |   Resolution:
       Keywords:  full               |    Merged in:
  subcategories, homset              |    Reviewers:  Darij Grinberg,
        Authors:  Nicolas M. ThiƩry  |  Travis Scrimshaw
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  public/categories/full_subcategories-16340|  
d4c7a88563a397291b6cd5ddadb8f574cc1eedb5
   Dependencies:                     |     Stopgaps:
-------------------------------------+-------------------------------------

Comment (by pbruin):

 (cut out of previous comment since this is somewhat off topic)

 Replying to [comment:38 nthiery]:

 > In particular, it becomes painful for categories with axioms or
 functorial construction
 > categories where the super categories are computed automatically for
 > you.

 What is a functorial construction category?  From the documentation it
 appears that the idea is that one first defines a construction in some
 "abstract" sense, and only then decides in which category it takes its
 values, or even to construct a completely new category for this.  I
 realise that the code doesn't have to follow mathematical definitions
 exactly, but this seems to be quite the opposite of the usual pattern of
 doing things, where defining a function, functor or natural transformation
 presupposes that a domain and codomain have been fixed.  In general this
 is essential because the function (etc.) that one defines, and its
 properties, depend on these choices.  I am somewhat worried that the Sage
 implementation might rely (maybe just in subtle ways) on the intuition
 behind the cases where this advance choice of domain and codomain doesn't
 matter so much.

--
Ticket URL: <http://trac.sagemath.org/ticket/16340#comment:41>
Sage <http://www.sagemath.org>
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