[Merged by Bors] - feat(CategoryTheory/Sites/Over): add Presieve.overEquiv

[tb65536]

This PR adds Presieve.overEquiv, the presieve version of the existing Sieve.overEquiv. I also upgraded these equivs to order isomorphisms, and fixed some defeq abuse at the same time.

Partial help from Claude on a couple of the proofs, all code was ultimately written and golfed by me.

---

[github-actions]

PR summary 88ef7429f9

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff (regex)

+ Presieve.map_le_functorPushforward
+ arrows_mono
+ functorPullback_functorPushforward_overForget
+ functorPullback_map_overForget
+ functorPushforward_functorPullback_overForget
+ functorPushforward_overForget_arrows
+ map_functorPullback_overForget
++- overEquiv
- Presieve.map_functorPullback_overForget

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

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

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 88ef742).

• +11 new declarations
• −0 removed declarations

+CategoryTheory.Presieve.functorPullback_map_overForget
+CategoryTheory.Presieve.map_le_functorPushforward
+CategoryTheory.Presieve.overEquiv
+CategoryTheory.Presieve.overEquiv_apply
+CategoryTheory.Presieve.overEquiv_symm_apply
+CategoryTheory.Sieve.arrows_mono
+CategoryTheory.Sieve.functorPullback_functorPushforward_overForget
+CategoryTheory.Sieve.functorPushforward_functorPullback_overForget
+CategoryTheory.Sieve.functorPushforward_overForget_arrows
+CategoryTheory.Sieve.overEquiv_apply
+CategoryTheory.Sieve.overEquiv_symm_apply

---

Decrease in strong tech debt: (relative, absolute) = (1.45, 0.00)

Current number	Change	Type (strong)
4514	-1	backward.defeqAttrib.useBackward
5624	-2	backward.isDefEq.respectTransparency

No changes to weak technical debt.

Current commit 88ef7429f9
Reference commit ae861491c1

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/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).

[erdOne]

Thanks!
maintainer merge

[github-actions]

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

[joelriou]

Thanks!

bors merge

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Build
• ci (staging) / Test and lint
• ci (staging) / Lint style
• ci (staging) / Post-Build Step
• ci (staging) / Post-CI job