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[Merged by Bors] - feat(Topology/Profinite): extending cones in Profinite and LightProfinite#14382

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[Merged by Bors] - feat(Topology/Profinite): extending cones in Profinite and LightProfinite#14382
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dagur/ProfiniteExtend

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@dagurtomas dagurtomas commented Jul 3, 2024

Let (Sᵢ)_{i : I} be a family of finite sets indexed by a cofiltered category I and let S be
its limit in Profinite. Let G be a functor from Profinite to a category C and suppose that
G preserves the limit described above. Suppose further that the projection maps S ⟶ Sᵢ are
epimorphic for all i. Then G.obj S is isomorphic to a limit indexed by
StructuredArrow S toProfinite (see Profinite.Extend.isLimitCone).

We also provide the dual result for a functor of the form G : Profiniteᵒᵖ ⥤ C.


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github-actions bot commented Jul 3, 2024

PR summary 2460397ecb

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference
Mathlib.Topology.Category.Profinite.Extend 1351
Mathlib.Topology.Category.LightProfinite.Extend 1359

Declarations diff

+ exists_hom
+ instance (i : DiscreteQuotient S) : Epi (S.asLimitCone.π.app i)
+ instance (i : ℕᵒᵖ) : Epi (S.asLimitCone.π.app i)
+ instance : lightToProfinite.PreservesEpimorphisms
++ asLimit'
++ asLimitCone'
++ cocone
++ cone
++ diagram'
++ fintypeDiagram'
++ functor
++ functorOp
++ functorOp_final
++ functor_initial
++ isColimitCocone
++ isLimitCone
++ lim'

You can run this locally as follows
## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

@dagurtomas dagurtomas added the WIP Work in progress label Jul 3, 2024
@ghost ghost added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Jul 17, 2024
@ghost ghost removed the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Jul 31, 2024
@dagurtomas dagurtomas changed the title feat(Topology/Profinite): profinite sets as Kan extensions feat(Topology/Profinite): extending cones in Profinite and LightProfinite Aug 6, 2024
@dagurtomas dagurtomas added t-category-theory Category theory t-topology Topological spaces, uniform spaces, metric spaces, filters and removed WIP Work in progress labels Aug 6, 2024
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Looks good! I had a few suggestions which are fairly minor. I assume you're preparing to relate Profinite.extend and friends to Kan extensions?

@adamtopaz adamtopaz added the awaiting-author A reviewer has asked the author a question or requested changes. label Aug 29, 2024
dagurtomas and others added 3 commits August 30, 2024 10:30
Co-authored-by: Adam Topaz <adamtopaz@users.noreply.github.com>
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I assume you're preparing to relate Profinite.extend and friends to Kan extensions?

Yes, see #15566, specifcally https://github.com/leanprover-community/mathlib4/blob/f7f43971b46ef2041f517cdd1c4d9440158a9dde/Mathlib/Condensed/Discrete/Colimit.lean

@dagurtomas dagurtomas removed the awaiting-author A reviewer has asked the author a question or requested changes. label Aug 30, 2024
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Thanks!
bors r+

@github-actions github-actions bot added the ready-to-merge This PR has been sent to bors. label Aug 31, 2024
mathlib-bors bot pushed a commit that referenced this pull request Aug 31, 2024
…ofinite` (#14382)

Let `(Sᵢ)_{i : I}` be a family of finite sets indexed by a cofiltered category `I` and let `S` be
its limit in `Profinite`. Let `G` be a functor from `Profinite` to a category `C` and suppose that
`G` preserves the limit described above. Suppose further that the projection maps `S ⟶ Sᵢ` are
epimorphic for all `i`. Then `G.obj S` is isomorphic to a limit indexed by
`StructuredArrow S toProfinite` (see `Profinite.Extend.isLimitCone`).

We also provide the dual result for a functor of the form `G : Profiniteᵒᵖ ⥤ C`.
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mathlib-bors bot commented Aug 31, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat(Topology/Profinite): extending cones in Profinite and LightProfinite [Merged by Bors] - feat(Topology/Profinite): extending cones in Profinite and LightProfinite Aug 31, 2024
@mathlib-bors mathlib-bors bot closed this Aug 31, 2024
@mathlib-bors mathlib-bors bot deleted the dagur/ProfiniteExtend branch August 31, 2024 20:17
bjoernkjoshanssen pushed a commit that referenced this pull request Sep 9, 2024
…ofinite` (#14382)

Let `(Sᵢ)_{i : I}` be a family of finite sets indexed by a cofiltered category `I` and let `S` be
its limit in `Profinite`. Let `G` be a functor from `Profinite` to a category `C` and suppose that
`G` preserves the limit described above. Suppose further that the projection maps `S ⟶ Sᵢ` are
epimorphic for all `i`. Then `G.obj S` is isomorphic to a limit indexed by
`StructuredArrow S toProfinite` (see `Profinite.Extend.isLimitCone`).

We also provide the dual result for a functor of the form `G : Profiniteᵒᵖ ⥤ C`.
bjoernkjoshanssen pushed a commit that referenced this pull request Sep 9, 2024
…ofinite` (#14382)

Let `(Sᵢ)_{i : I}` be a family of finite sets indexed by a cofiltered category `I` and let `S` be
its limit in `Profinite`. Let `G` be a functor from `Profinite` to a category `C` and suppose that
`G` preserves the limit described above. Suppose further that the projection maps `S ⟶ Sᵢ` are
epimorphic for all `i`. Then `G.obj S` is isomorphic to a limit indexed by
`StructuredArrow S toProfinite` (see `Profinite.Extend.isLimitCone`).

We also provide the dual result for a functor of the form `G : Profiniteᵒᵖ ⥤ C`.
bjoernkjoshanssen pushed a commit that referenced this pull request Sep 12, 2024
…ofinite` (#14382)

Let `(Sᵢ)_{i : I}` be a family of finite sets indexed by a cofiltered category `I` and let `S` be
its limit in `Profinite`. Let `G` be a functor from `Profinite` to a category `C` and suppose that
`G` preserves the limit described above. Suppose further that the projection maps `S ⟶ Sᵢ` are
epimorphic for all `i`. Then `G.obj S` is isomorphic to a limit indexed by
`StructuredArrow S toProfinite` (see `Profinite.Extend.isLimitCone`).

We also provide the dual result for a functor of the form `G : Profiniteᵒᵖ ⥤ C`.
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