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feat(Algebra/Category/ModuleCat/Sheaf): isQuasicoherent and isFinitePresentation are closed under isomorphisms#37532

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feat(Algebra/Category/ModuleCat/Sheaf): isQuasicoherent and isFinitePresentation are closed under isomorphisms#37532
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justus-springer:justus/quasicoherent_closed_under_iso

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@justus-springer justus-springer commented Apr 2, 2026

Also slightly changes the definition of Presentation.IsFinite to use GeneratingSections.IsFiniteType in both fields, which makes the interface more consistent.


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github-actions bot commented Apr 2, 2026

PR summary 1692ef2d66

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference

Declarations diff

+ Hom.over
+ Presentation.IsFinite.finite_relations
+ QuasicoherentData.of_isIso
+ instance (σ : M.GeneratingSections) (p : M ⟶ N) [Epi p] [σ.IsFiniteType] :
+ instance : (isFinitePresentation R).IsClosedUnderIsomorphisms
+ instance : (isQuasicoherent R).IsClosedUnderIsomorphisms
+ instance {M N : SheafOfModules.{u} R} (f : M ⟶ N) [IsIso f]
+ instance {M N : SheafOfModules.{u} R} (f : M ⟶ N) [IsIso f] (σ : M.QuasicoherentData)

You can run this locally as follows
## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.


No changes to technical debt.

You can run this locally as

./scripts/reporting/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).

@github-actions github-actions bot added the t-algebra Algebra (groups, rings, fields, etc) label Apr 2, 2026
@justus-springer justus-springer added the t-algebraic-geometry Algebraic geometry label Apr 8, 2026
@chrisflav chrisflav added the awaiting-author A reviewer has asked the author a question or requested changes. label Apr 13, 2026
@justus-springer justus-springer added awaiting-CI This PR does not pass CI yet. This label is automatically removed once it does. and removed awaiting-author A reviewer has asked the author a question or requested changes. labels Apr 14, 2026
@github-actions github-actions bot removed the awaiting-CI This PR does not pass CI yet. This label is automatically removed once it does. label Apr 14, 2026
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LGTM, modulo one comment.


/-- Mapping quasicoherent data under an isomorphism. -/
@[simps]
noncomputable def QuasicoherentData.of_isIso {M N : SheafOfModules.{u} R} (f : M ⟶ N) [IsIso f]
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Suggested change
noncomputable def QuasicoherentData.of_isIso {M N : SheafOfModules.{u} R} (f : M ⟶ N) [IsIso f]
noncomputable def QuasicoherentData.ofIsIso {M N : SheafOfModules.{u} R} (f : M ⟶ N) [IsIso f]

because this is a def. If you want, you can also fix Presentation.of_isIso.

@chrisflav chrisflav added the awaiting-author A reviewer has asked the author a question or requested changes. label Apr 14, 2026
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