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[Merged by Bors] - feat(CategoryTheory/Triangulated/Adjunction): the left adjoint of a triangulated functor is triangulated#20543

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[Merged by Bors] - feat(CategoryTheory/Triangulated/Adjunction): the left adjoint of a triangulated functor is triangulated#20543
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SM.adjointTriangulated2

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If a functor G : D ⥤ C between pretriangulated categories is triangulated, and if we have an adjunction F ⊣ G (that commutes with the shifts), then F is also a triangulated functor.

We prove this from the symmetric statement (F triangulated implies G triangulated) using opposite categories.


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@mathlib4-dependent-issues-bot mathlib4-dependent-issues-bot removed the blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) label Jan 10, 2025
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Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>
Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>
@joelriou joelriou added the awaiting-author A reviewer has asked the author a question or requested changes. label Jan 11, 2025
smorel394 and others added 2 commits January 12, 2025 10:42
Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>
Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>
@smorel394 smorel394 removed the awaiting-author A reviewer has asked the author a question or requested changes. label Jan 12, 2025
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Thanks!

bors merge

@ghost ghost added the ready-to-merge This PR has been sent to bors. label Jan 12, 2025
mathlib-bors bot pushed a commit that referenced this pull request Jan 12, 2025
…riangulated functor is triangulated (#20543)

If a functor `G : D ⥤ C` between pretriangulated categories is triangulated, and if we have an adjunction `F ⊣ G` (that commutes with the shifts), then `F` is also a triangulated functor.

We prove this from the symmetric statement (`F` triangulated implies `G` triangulated) using opposite categories.

- [ ] depends on: #20363




Co-authored-by: smorel394 <67864981+smorel394@users.noreply.github.com>
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mathlib-bors bot commented Jan 12, 2025

Pull request successfully merged into master.

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@mathlib-bors mathlib-bors bot changed the title feat(CategoryTheory/Triangulated/Adjunction): the left adjoint of a triangulated functor is triangulated [Merged by Bors] - feat(CategoryTheory/Triangulated/Adjunction): the left adjoint of a triangulated functor is triangulated Jan 12, 2025
@mathlib-bors mathlib-bors bot closed this Jan 12, 2025
@mathlib-bors mathlib-bors bot deleted the SM.adjointTriangulated2 branch January 12, 2025 15:09
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