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[Merged by Bors] - feat(category_theory/limits): preservation of zero morphisms #12068

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@TwoFX TwoFX commented Feb 16, 2022


Open in Gitpod

@TwoFX TwoFX added awaiting-review The author would like community review of the PR awaiting-CI The author would like to see what CI has to say before doing more work. labels Feb 16, 2022
@TwoFX TwoFX removed the awaiting-CI The author would like to see what CI has to say before doing more work. label Feb 16, 2022
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LGTM, probably @adamtopaz or @jcommelin ought to look too

F.map (0 : X ⟶ Y) = 0 :=
preserves_zero_morphisms.map_zero' _ _

lemma equivalence_preserves_zero_morphisms (F : C ≌ D) : preserves_zero_morphisms F.functor :=
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Is this a special case of something slightly more general, maybe that adjoints preserve zero morphisms? I don't know the maths here enough to be sure

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Earlier today I proved on paper that fully faithful is enough, and I'll generalize the proof soon. lt might also be true for adjoints, I'll think about that.

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I managed to prove it for adjoints :) I'll update the PR tomorrow. (Edit: Done.)

@TwoFX TwoFX added WIP Work in progress and removed awaiting-review The author would like community review of the PR labels Feb 16, 2022
@TwoFX TwoFX added awaiting-review The author would like community review of the PR and removed WIP Work in progress labels Feb 17, 2022
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Thanks!

bors merge


We provide the following results:
* Left adjoints and right adjoints preserve zero morphisms;
* full functors preserves zero morphisms;
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Suggested change
* full functors preserves zero morphisms;
* full functors preserve zero morphisms;

@leanprover-community-bot-assistant leanprover-community-bot-assistant added ready-to-merge All that is left is for bors to build and merge this PR. (Remember you need to say `bors r+`.) and removed awaiting-review The author would like community review of the PR labels Feb 17, 2022
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bors bot commented Feb 17, 2022

Pull request successfully merged into master.

Build succeeded:

@bors bors bot changed the title feat(category_theory/limits): preservation of zero morphisms [Merged by Bors] - feat(category_theory/limits): preservation of zero morphisms Feb 17, 2022
@bors bors bot closed this Feb 17, 2022
@bors bors bot deleted the preserves_zero branch February 17, 2022 19:35
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3 participants