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feat(CategoryTheory): criterion for `ObjectProperty.ind` in finitely accessible categories

Open chrisflav opened this issue 1 month ago • 3 comments

We show that if C is finitely accessible and P implies finitely presentable, then X satisfies ind P if and only if every morphism Z ⟶ X from a finitely presentable object factors via an object satisfying W. We also add the analogous statement for morphism properties.

From Proetale.


  • [x] depends on: #33001

Open in Gitpod

chrisflav avatar Dec 17 '25 11:12 chrisflav

PR summary 99bc1514ad

Import changes exceeding 2%

% File
+5.71% Mathlib.CategoryTheory.MorphismProperty.Ind
+8.08% Mathlib.CategoryTheory.ObjectProperty.Ind

Import changes for modified files

Dependency changes

File Base Count Head Count Change
Mathlib.CategoryTheory.ObjectProperty.Ind 743 803 +60 (+8.08%)
Mathlib.CategoryTheory.MorphismProperty.Ind 770 814 +44 (+5.71%)
Mathlib.CategoryTheory.Presentable.Dense 798 801 +3 (+0.38%)
Import changes for all files
Files Import difference
Mathlib.CategoryTheory.Presentable.Dense 3
Mathlib.CategoryTheory.MorphismProperty.Ind 44
Mathlib.CategoryTheory.ObjectProperty.Ind 60

Declarations diff

+ IsFinitelyAccessibleCategory + IsLocallyFinitelyPresentable + ObjectProperty.isFinitelyPresentable_eq_isCardinalPresentable + instance (X : (ObjectProperty.isFinitelyPresentable.{w} C).FullSubcategory) : + instance [IsFinitelyAccessibleCategory.{w} C] (X : C) : + of_essentiallySmall_index ++ ind_iff_exists ++ instance [IsFinitelyAccessibleCategory.{w} C] :

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).

github-actions[bot] avatar Dec 17 '25 11:12 github-actions[bot]

This PR/issue depends on:

  • ~~leanprover-community/mathlib4#33001~~ By Dependent Issues (🤖). Happy coding!

This pull request has conflicts, please merge master and resolve them.

Thanks!

maintainer merge

robin-carlier avatar Dec 19 '25 19:12 robin-carlier

🚀 Pull request has been placed on the maintainer queue by robin-carlier.

github-actions[bot] avatar Dec 19 '25 19:12 github-actions[bot]

Thanks!

bors merge

joelriou avatar Dec 20 '25 10:12 joelriou

Pull request successfully merged into master.

Build succeeded:

mathlib-bors[bot] avatar Dec 20 '25 10:12 mathlib-bors[bot]