Opened 19 months ago

Last modified 5 months ago

#31241 new enhancement

Forgetful Functors for Manifolds — at Version 3

Reported by: gh-mjungmath Owned by:
Priority: major Milestone: sage-9.7
Component: manifolds Keywords:
Cc: tscrim, egourgoulhon, mkoeppe Merged in:
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Report Upstream: N/A Work issues:
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Description (last modified by gh-mjungmath)

It would be nice to allow forgetful functors for manifolds. In particular:

  • differentiable manifolds -> topological manifolds
  • (Pseudo-)Riemannian manifolds -> differentiable manifolds
  • topological manifolds -> sets (?)

and probably even more. The last point, if getting to work somehow, might also be useful in terms of #30832.

At the moment, we have the following behavior (which could be seen as a bug):

sage: from sage.categories.functor import ForgetfulFunctor
sage: from sage.categories.manifolds import Manifolds
sage: F = ForgetfulFunctor(Manifolds(RR).Differentiable(), Manifolds(RR).Topological())
sage: M = Manifold(2, 'M')
sage: F(M)
2-dimensional differentiable manifold M

Change History (3)

comment:1 Changed 19 months ago by gh-mjungmath

  • Description modified (diff)

comment:2 Changed 19 months ago by gh-mjungmath

  • Description modified (diff)

comment:3 Changed 19 months ago by gh-mjungmath

  • Description modified (diff)
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