#18175: Implement categories for topological and metric spaces and related
categories
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       Reporter:  tscrim             |        Owner:  tscrim
           Type:  enhancement        |       Status:  new
       Priority:  major              |    Milestone:  sage-6.6
      Component:  categories         |   Resolution:
       Keywords:  geometry,          |    Merged in:
  topology, sd67                     |    Reviewers:
        Authors:  Travis Scrimshaw   |  Work issues:
Report Upstream:  N/A                |       Commit:
         Branch:                     |  fcc3273fbb9e83da6c61027463e3ed4582009514
  public/categories/topological_metric_spaces-18175|     Stopgaps:
   Dependencies:  #18174 #17160      |
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Comment (by egourgoulhon):

 Replying to [comment:11 tscrim]:
 > Replying to [comment:9 egourgoulhon]:
 > > Replying to [comment:8 tscrim]:
 > > > I wasn't sure about the dimension making sense for manifolds unless
 they are connected as far as my definition. Mainly do we want the disjoint
 union of a 1-sphere and 2-sphere be a manifold? (Current definition is
 yes). If so, then is the dimension the maximal dimension of each
 component? I will leave the decision up to you.
 > >
 > > For all the textbook definitions I am aware of, the disjoint union of
 a 1-sphere and a 2-sphere is *not* a manifold. In other words, the
 dimension is unique among all the connected components of the manifold. So
 I think the dimension should be at the level of `Manifolds`.
 >
 > I split the difference in that I kept a more general definition, but I
 had dimension be the maximum of the dimensions of each connected component
 so you don't necessarily have to specify connected.

 Do you have a reference for such a definition of a manifold ? It seems
 non-standard (*) to me, but I might be wrong.
 (*) the standard being that the dimension is the same for all the
 connected components.

--
Ticket URL: <http://trac.sagemath.org/ticket/18175#comment:12>
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