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[Merged by Bors] - feat(CategoryTheory/Galois): fundamental group is limit of automorphism groups#12843

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[Merged by Bors] - feat(CategoryTheory/Galois): fundamental group is limit of automorphism groups#12843
chrisflav wants to merge 26 commits intomasterfrom
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@chrisflav chrisflav commented May 12, 2024

We show that the automorphism group of a fiber functor is isomorphic to the limit of the automorphism groups of all Galois objects.

From this we deduce that the automorphism group of a fiber functor acts transitively on the fibers of connected objects. This is the last essential step towards showing that a fiber functor induces a fully faithful embedding into the category of finite Aut F-types.


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@chrisflav chrisflav added awaiting-review awaiting-CI This PR does not pass CI yet. This label is automatically removed once it does. t-category-theory Category theory labels May 12, 2024
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ghost commented May 23, 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 May 24, 2024
@joelriou joelriou added awaiting-author A reviewer has asked the author a question or requested changes. and removed awaiting-review labels May 24, 2024
@joelriou joelriou added awaiting-author A reviewer has asked the author a question or requested changes. and removed awaiting-review labels Jun 7, 2024
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github-actions bot commented Jun 7, 2024

Import summary

Dependency changes
File Base Count Head Count Change
Mathlib.CategoryTheory.Galois.Prorepresentability 944 1021 +77 (+8.16%)
Mathlib.Algebra.Category.MonCat.Basic 486 487 +1 (+0.21%)
Mathlib.Algebra.Category.GroupCat.Basic 488 489 +1 (+0.20%)
Mathlib.CategoryTheory.Galois.Basic 849 850 +1 (+0.12%)

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joelriou commented Jun 7, 2024

Thanks!

bors d+

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mathlib-bors bot commented Jun 7, 2024

✌️ chrisflav can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

@github-actions github-actions bot added delegated This pull request has been delegated to the PR author (or occasionally another non-maintainer). and removed awaiting-review labels Jun 7, 2024
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github-actions bot commented Jun 7, 2024

PR summary

Import changes

Dependency changes

File Base Count Head Count Change
Mathlib.CategoryTheory.Galois.Prorepresentability 944 1021 +77 (+8.16%)
Mathlib.Algebra.Category.MonCat.Basic 486 487 +1 (+0.21%)
Mathlib.Algebra.Category.GroupCat.Basic 488 489 +1 (+0.20%)
Mathlib.CategoryTheory.Galois.Basic 849 850 +1 (+0.12%)

Declarations diff

+ AutGalois
+ AutGalois.ext
+ AutGalois.π
+ AutGalois.π_apply
+ AutGalois.π_surjective
+ FiberFunctor.isPretransitive_of_isConnected
+ FiberFunctor.isPretransitive_of_isGalois
+ FibreFunctor.end_isIso
+ FibreFunctor.end_isUnit
+ autGaloisSystem_map_surjective
+ autIsoFibers
+ autIsoFibers_inv_app
+ autMulEquivAutGalois
+ autMulEquivAutGalois_symm_app
+ autMulEquivAutGalois_π
+ endEquivAutGalois
+ endEquivAutGalois_mul
+ endEquivAutGalois_π
+ endEquivSectionsFibers
+ endEquivSectionsFibers_π
+ endMulEquivAutGalois
+ endMulEquivAutGalois_pi
+ instance (X : C) : MulAction (Aut F) (F.obj X)
+ instance : Group (AutGalois F)
+ mulAction_def
+ sectionsπMonoidHom
++++ uliftFunctor

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

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

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mathlib-bors bot commented Jun 8, 2024

✌️ chrisflav can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

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bors r+

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Thanks for the review @joelriou !

mathlib-bors bot pushed a commit that referenced this pull request Jun 8, 2024
…sm groups (#12843)

We show that the automorphism group of a fiber functor is isomorphic to the limit of the automorphism groups of all Galois objects.

From this we deduce that the automorphism group of a fiber functor acts transitively on the fibers of connected objects. This is the last essential step towards showing that a fiber functor induces a fully faithful embedding into the category of finite `Aut F`-types.
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mathlib-bors bot commented Jun 8, 2024

Build failed:

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bors r+

mathlib-bors bot pushed a commit that referenced this pull request Jun 8, 2024
…sm groups (#12843)

We show that the automorphism group of a fiber functor is isomorphic to the limit of the automorphism groups of all Galois objects.

From this we deduce that the automorphism group of a fiber functor acts transitively on the fibers of connected objects. This is the last essential step towards showing that a fiber functor induces a fully faithful embedding into the category of finite `Aut F`-types.
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mathlib-bors bot commented Jun 8, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat(CategoryTheory/Galois): fundamental group is limit of automorphism groups [Merged by Bors] - feat(CategoryTheory/Galois): fundamental group is limit of automorphism groups Jun 8, 2024
@mathlib-bors mathlib-bors bot closed this Jun 8, 2024
@mathlib-bors mathlib-bors bot deleted the chrisflav/galois-prorep.2 branch June 8, 2024 17:32
AntoineChambert-Loir pushed a commit that referenced this pull request Jun 20, 2024
…sm groups (#12843)

We show that the automorphism group of a fiber functor is isomorphic to the limit of the automorphism groups of all Galois objects.

From this we deduce that the automorphism group of a fiber functor acts transitively on the fibers of connected objects. This is the last essential step towards showing that a fiber functor induces a fully faithful embedding into the category of finite `Aut F`-types.
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