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[Merged by Bors] - feat(topology/algebra/uniform_group): the quotient of a first countable complete topological group by a normal subgroup is itself complete #16368
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j-loreaux
commented
Sep 4, 2022
[@complete_space G (topological_group.to_uniform_space G)] : | ||
@complete_space (G ⧸ N) (topological_group.to_uniform_space (G ⧸ N)) := |
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I think it would make sense to add a note about why this topological_group.to_uniform_space
stuff is needed here and in the next instance.
Let me know if the changes I made were what you were looking for. |
Yes, this looks good. Out of curiosity, does the last instance actually kick in in these most common use cases where the uniform space structure is defeq with this one? |
Yes, I checked that. Well, it does for |
Would it make sense to add extra instances for submodules and ideals so we don't have to do this manually? |
It's in #16446. It needs to be there because we didn't have norm structures on other kinds of quotients yet. |
Ah I see! In that case LGTM. bors r+ |
…le complete topological group by a normal subgroup is itself complete (#16368)
Pull request successfully merged into master. Build succeeded: |
…tients of groups to quotients of modules by submodules and of rings by ideals (#16446) This takes the existing norm structures on quotients of additive groups and transfers it along the definitional equality to quotients of modules by submodules and quotients of rings by ideals. In addition, this puts the extra norm structures on these objects where appropriate including `complete_space`, `normed_space`, `semi_normed_comm_ring`, `normed_comm_ring` and `normed_algebra`. - [x] depends on: #16368
…le complete topological group by a normal subgroup is itself complete (#16368)
…tients of groups to quotients of modules by submodules and of rings by ideals (#16446) This takes the existing norm structures on quotients of additive groups and transfers it along the definitional equality to quotients of modules by submodules and quotients of rings by ideals. In addition, this puts the extra norm structures on these objects where appropriate including `complete_space`, `normed_space`, `semi_normed_comm_ring`, `normed_comm_ring` and `normed_algebra`. - [x] depends on: #16368