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[Merged by Bors] - chore(CategoryTheory/Shift): fix NatTrans.CommShift#20364

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[Merged by Bors] - chore(CategoryTheory/Shift): fix NatTrans.CommShift#20364
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@joelriou joelriou commented Dec 31, 2024

This PR improves some proofs about NatTrans.CommShift (the commutation of a natural transformation to shifts). The field comm' of NatTrans.CommShift had an unnecessary ' in it, it is renamed shift_comm, and API lemmas are moved from NatTrans.CommShift to the NatTrans namespace (where comm becomes shift_comm and comm_app becomes shift_app_comm).


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@joelriou joelriou added the t-category-theory Category theory label Dec 31, 2024
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PR summary 3d7431c928

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference

Declarations diff

+ CommShift.app_shift
+ CommShift.comm
+ CommShift.comm'
+ CommShift.comm_app
+ CommShift.shift_app
+ shift_app_comm
+ shift_comm
- comm
- comm_app

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.


Decrease in tech debt: (relative, absolute) = (2.00, 0.00)
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1514 -2 erw

Current commit 3d7431c928
Reference commit e92b32904d

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./scripts/technical-debt-metrics.sh pr_summary
  • The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
  • The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

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Seems fine to me.

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erdOne commented Jan 3, 2025

Thanks!
maintainer merge

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github-actions bot commented Jan 3, 2025

🚀 Pull request has been placed on the maintainer queue by erdOne.

@github-actions github-actions bot added the maintainer-merge A reviewer has approved the changed; awaiting maintainer approval. label Jan 3, 2025
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kbuzzard commented Jan 3, 2025

Thanks!

bors merge

@ghost ghost added the ready-to-merge This PR has been sent to bors. label Jan 3, 2025
mathlib-bors bot pushed a commit that referenced this pull request Jan 3, 2025
This PR improves some proofs about `NatTrans.CommShift` (the commutation of a natural transformation to shifts). The field `comm'` of `NatTrans.CommShift` had an unnecessary `'` in it, it is renamed `shift_comm`, and API lemmas are moved from `NatTrans.CommShift` to the `NatTrans` namespace (where `comm` becomes `shift_comm` and `comm_app` becomes `shift_app_comm`).
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mathlib-bors bot commented Jan 3, 2025

Pull request successfully merged into master.

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@mathlib-bors mathlib-bors bot changed the title chore(CategoryTheory/Shift): fix NatTrans.CommShift [Merged by Bors] - chore(CategoryTheory/Shift): fix NatTrans.CommShift Jan 3, 2025
@mathlib-bors mathlib-bors bot closed this Jan 3, 2025
@mathlib-bors mathlib-bors bot deleted the functor-commshif-remove-unnecessary-lemmas branch January 3, 2025 12:07
mathlib-bors bot pushed a commit that referenced this pull request Jan 6, 2025
…Shift` (#20337)

Provide instances that say that `Adjunction.CommShift` holds for the identity adjunction and is stable by composition, as well as similar instances for `Equivalence.CommShift`.

- [ ] depends on: #20364
- [ ] depends on: #20490



Co-authored-by: Joël Riou <37772949+joelriou@users.noreply.github.com>
Co-authored-by: smorel394 <67864981+smorel394@users.noreply.github.com>
mathlib-bors bot pushed a commit that referenced this pull request Jan 10, 2025
…: `CommShift` structures on adjunctions are compatible with opposites and pullbacks (#20363)

Suppose that we use categories `C` and `D` equiped with a shifts by an additive monoid `A`, functors `F,F' : C ⥤ D`, a functor `G : D ⥤ C`, a natural transformation `τ : F ⟶ F'` and an adjunction `adj` between `F` and `G`.

* For any map of additive monoids `φ : B →+ A`, we define type synonyms `PullbackShift.functor F φ` for `F`, `PullbackShift.natTrans τ φ` for `τ`, and `PullbackShift.adjunction adj φ` for `adj`. We then prove that a `CommShift` structure on `F` (resp. `τ`, resp. `adj`) induces a `CommShift` structure on `PullbackShift.functor F φ` (resp. `PullbackShift.natTrans τ φ`, resp. `PullbackShift.adjunction adj φ` ).

* Similarly, we define type synonyms `OppositeShift.functor A F` for `F.op`, `OppositeShift.natTrans A τ` for `τ.op` and `OppositeShift.adjunction A adj` for `adj.op`, and prove that a `CommShift` structure on `F` (resp. `τ`, resp. `adj`) induces a `CommShift` structure on `OppositeShift.functor A F` (resp. `OppositeShift.natTrans A τ`, resp. `OppositeShift.adjunction A adj` ) for the naive shifts on the opposite categories.

* The point of the second part is to reserve `F.op` etc to carry `CommShift` structures for the modified shift on the opposite categories used in the theory of (pre)triangulated categories. We illustrate this by simplifying the definition of the instance `commShiftOpInt` (a `CommShift ℤ` instance on `F.op` for the modified shifts) in the file `Triangulated.Opposite.Functor`.



- [x] depends on: #20364



Co-authored-by: smorel394 <67864981+smorel394@users.noreply.github.com>
grunweg pushed a commit that referenced this pull request Jan 11, 2025
…: `CommShift` structures on adjunctions are compatible with opposites and pullbacks (#20363)

Suppose that we use categories `C` and `D` equiped with a shifts by an additive monoid `A`, functors `F,F' : C ⥤ D`, a functor `G : D ⥤ C`, a natural transformation `τ : F ⟶ F'` and an adjunction `adj` between `F` and `G`.

* For any map of additive monoids `φ : B →+ A`, we define type synonyms `PullbackShift.functor F φ` for `F`, `PullbackShift.natTrans τ φ` for `τ`, and `PullbackShift.adjunction adj φ` for `adj`. We then prove that a `CommShift` structure on `F` (resp. `τ`, resp. `adj`) induces a `CommShift` structure on `PullbackShift.functor F φ` (resp. `PullbackShift.natTrans τ φ`, resp. `PullbackShift.adjunction adj φ` ).

* Similarly, we define type synonyms `OppositeShift.functor A F` for `F.op`, `OppositeShift.natTrans A τ` for `τ.op` and `OppositeShift.adjunction A adj` for `adj.op`, and prove that a `CommShift` structure on `F` (resp. `τ`, resp. `adj`) induces a `CommShift` structure on `OppositeShift.functor A F` (resp. `OppositeShift.natTrans A τ`, resp. `OppositeShift.adjunction A adj` ) for the naive shifts on the opposite categories.

* The point of the second part is to reserve `F.op` etc to carry `CommShift` structures for the modified shift on the opposite categories used in the theory of (pre)triangulated categories. We illustrate this by simplifying the definition of the instance `commShiftOpInt` (a `CommShift ℤ` instance on `F.op` for the modified shifts) in the file `Triangulated.Opposite.Functor`.



- [x] depends on: #20364



Co-authored-by: smorel394 <67864981+smorel394@users.noreply.github.com>
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