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[Merged by Bors] - feat(Mathlib/RingTheory/Ideal/QuotientOperations): First Isomorphism Theorem for algebras #11027

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We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.


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@AntoineChambert-Loir AntoineChambert-Loir added awaiting-review The author would like community review of the PR and removed awaiting-review The author would like community review of the PR labels Feb 27, 2024
@AntoineChambert-Loir AntoineChambert-Loir added the awaiting-review The author would like community review of the PR label Feb 28, 2024
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Thanks 🎉

bors merge

@leanprover-community-mathlib4-bot leanprover-community-mathlib4-bot added ready-to-merge This PR has been sent to bors. and removed awaiting-review The author would like community review of the PR labels Feb 28, 2024
mathlib-bors bot pushed a commit that referenced this pull request Feb 28, 2024
…Theorem for algebras (#11027)

We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.



Co-authored-by: Antoine Chambert-Loir <antoine.chambert-loir@math.univ-paris-diderot.fr>
Comment on lines +654 to +656
{A B : Type*} [CommRing A] [Algebra R A] [Semiring B] [Algebra R B]
(f : A →ₐ[R] B) :
(A ⧸ RingHom.ker f) ≃ₐ[R] f.range :=
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The linter should complain about the spacing indentation ...

Comment on lines +631 to +633
fun ⟨_y, hy⟩ =>
let ⟨x, hx⟩ := hy
⟨x, SetCoe.ext hx⟩
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Suggested change
fun ⟨_y, hy⟩ =>
let ⟨x, hx⟩ := hy
⟨x, SetCoe.ext hx⟩
RingHom.rangeRestrict_surjective f

(untested)


theorem ker_rangeRestrict (f : A →ₐ[R] B) :
RingHom.ker f.rangeRestrict = RingHom.ker f :=
Ideal.ext fun _ ↦ Subtype.ext_iff
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Suggested change
Ideal.ext fun _ ↦ Subtype.ext_iff
rfl

(untested)

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mathlib-bors bot commented Feb 28, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat(Mathlib/RingTheory/Ideal/QuotientOperations): First Isomorphism Theorem for algebras [Merged by Bors] - feat(Mathlib/RingTheory/Ideal/QuotientOperations): First Isomorphism Theorem for algebras Feb 28, 2024
@mathlib-bors mathlib-bors bot closed this Feb 28, 2024
@mathlib-bors mathlib-bors bot deleted the ACL/AlgHomFIT branch February 28, 2024 08:32
riccardobrasca pushed a commit that referenced this pull request Mar 1, 2024
…Theorem for algebras (#11027)

We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.



Co-authored-by: Antoine Chambert-Loir <antoine.chambert-loir@math.univ-paris-diderot.fr>
kbuzzard pushed a commit that referenced this pull request Mar 12, 2024
…Theorem for algebras (#11027)

We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.



Co-authored-by: Antoine Chambert-Loir <antoine.chambert-loir@math.univ-paris-diderot.fr>
dagurtomas pushed a commit that referenced this pull request Mar 22, 2024
…Theorem for algebras (#11027)

We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.



Co-authored-by: Antoine Chambert-Loir <antoine.chambert-loir@math.univ-paris-diderot.fr>
Louddy pushed a commit that referenced this pull request Apr 15, 2024
…Theorem for algebras (#11027)

We add the First Isomorphism Theorem for algebras.
(only the surjective version was present in mathlib).
We also adjust the docstring on top of the file.



Co-authored-by: Antoine Chambert-Loir <antoine.chambert-loir@math.univ-paris-diderot.fr>
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4 participants