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feat(CategoryTheory): deriving functors using a right derivability structure#23915

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jriou-derivability-structure-right-derives
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feat(CategoryTheory): deriving functors using a right derivability structure#23915
joelriou wants to merge 19 commits intomasterfrom
jriou-derivability-structure-right-derives

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@joelriou joelriou commented Apr 10, 2025

We develop the API for derived functors following the existence theorem obtained in #26374. If Φ is a localizer morphism, we introduce a predicate Φ.Derives F for a functor F saying that Φ.functor ⋙ F inverts the given class of morphisms, and in case Φ is a right derivability structure, we show that F admits a right derived functor, and we obtain a recognition lemma for this derived functor.

(In the future, this will be applied to the injective/projective/flat derivability structures.)


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@joelriou joelriou added WIP Work in progress t-category-theory Category theory labels Apr 10, 2025
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github-actions bot commented Apr 10, 2025

PR summary 32df3bc130

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference
Mathlib.CategoryTheory.Functor.Derived.PointwiseRightDerived (new file) 474
Mathlib.CategoryTheory.Localization.DerivabilityStructure.PointwiseRightDerived (new file) 644
Mathlib.CategoryTheory.Localization.DerivabilityStructure.Derives (new file) 645

Declarations diff

+ Derives
+ HasPointwiseRightDerivedFunctor
+ HasPointwiseRightDerivedFunctorAt
+ LeftExtension.isPointwiseLeftKanExtensionOfIsIso
+ hasColimit_comp_iff
+ hasLimit_comp_iff
+ hasLimit_equivalence_comp
+ hasLimit_of_equivalence_comp
+ hasPointwiseLeftKanExtensionAt_iff_of_equivalence
+ hasPointwiseLeftKanExtensionAt_iff_of_iso
+ hasPointwiseLeftKanExtensionAt_iff_of_iso'
+ hasPointwiseLeftKanExtensionAt_of_equivalence
+ hasPointwiseLeftKanExtension_of_hasPointwiseRightDerivedFunctor
+ hasPointwiseRightDerivedFunctor
+ hasPointwiseRightDerivedFunctorAt_iff
+ hasPointwiseRightDerivedFunctorAt_iff_of_isRightDerivabilityStructure
+ hasPointwiseRightDerivedFunctorAt_iff_of_mem
+ hasPointwiseRightDerivedFunctor_iff_of_isRightDerivabilityStructure
+ hasPointwiseRightDerivedFunctor_of_inverts
+ hasPointwiseRightKanExtensionAt_iff_of_equivalence
+ hasPointwiseRightKanExtensionAt_iff_of_iso
+ hasPointwiseRightKanExtensionAt_iff_of_iso'
+ hasPointwiseRightKanExtensionAt_of_equivalence
+ hasRightDerivedFunctor_of_hasPointwiseRightDerivedFunctor
+ instance :
+ isIso_comp_left_iff
+ isIso_comp_right_iff
+ isIso_of_isRightDerivedFunctor_of_inverts
+ isIso_α
+ isIso_α_iff_of_isRightDerivabilityStructure
+ isPointwiseLeftKanExtensionAtEquivOfIso'
+ isPointwiseLeftKanExtensionAtOfIso
+ isPointwiseLeftKanExtensionAtOfIso'
+ isPointwiseLeftKanExtensionOfHasPointwiseRightDerivedFunctor
+ isPointwiseLeftKanExtensionOfIso
+ isPointwiseRightKanExtensionAtEquivOfIso'
+ isPointwiseRightKanExtensionAtOfIso'
+ isRightDerivedFunctor_of_inverts
+ isRightDerivedFunctor_of_isIso_α
+ rightDerivedFunctorComparison
+ rightDerivedFunctorComparison_fac
+ rightDerivedFunctorComparison_fac_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.


No changes to technical debt.

You can run this locally as

./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).

@mathlib4-dependent-issues-bot mathlib4-dependent-issues-bot added the blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) label Apr 10, 2025
@leanprover-community-bot-assistant leanprover-community-bot-assistant added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Apr 28, 2025
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This pull request has conflicts, please merge master and resolve them.

@github-actions github-actions bot removed the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Apr 29, 2025
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This pull request has conflicts, please merge master and resolve them.

@leanprover-community-bot-assistant leanprover-community-bot-assistant added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label May 11, 2025
@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 Nov 8, 2025
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joelriou commented Nov 8, 2025

See #31400

@joelriou joelriou closed this Nov 8, 2025
@YaelDillies YaelDillies deleted the jriou-derivability-structure-right-derives branch March 29, 2026 12:40
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