[Merged by Bors] - feat(CategoryTheory): commutative group objects

[TwoFX]

---

• depends on: [Merged by Bors] - feat(CategoryTheory): group objects #21347
• depends on: [Merged by Bors] - feat(CategoryTheory): more API for ChosenFiniteProducts #21509

[github-actions]

PR summary 5cbd482ff0

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
Mathlib.CategoryTheory.Monoidal.CommGrp_ (new file)	620

---

Declarations diff

+ CommGrp_
+ comp'
+ comp_hom
+ forget
+ forget₂CommMon_
+ forget₂CommMon_comp_forget
+ forget₂CommMon_map_hom
+ forget₂CommMon_obj_mul
+ forget₂CommMon_obj_one
+ forget₂Grp_
+ forget₂Grp_comp_forget
+ forget₂Grp_map_hom
+ forget₂Grp_obj_mul
+ forget₂Grp_obj_one
+ fullyFaithfulForget₂CommMon_
+ fullyFaithfulForget₂Grp_
+ hom_ext
+ id'
+ id_hom
+ instance : (forget C).Faithful
+ instance : (forget₂CommMon_ C).Faithful := InducedCategory.faithful _
+ instance : (forget₂CommMon_ C).Full := InducedCategory.full _
+ instance : (forget₂Grp_ C).Faithful := InducedCategory.faithful _
+ instance : (forget₂Grp_ C).Full := InducedCategory.full _
+ instance : Category (CommGrp_ C)
+ instance : HasInitial (CommGrp_ C)
+ instance : Inhabited (CommGrp_ C)
+ mapCommGrp
+ mapCommGrpFunctor
+ mkIso
+ mkIso_hom_hom
+ mkIso_inv_hom
+ trivial
+ uniqueHomFromTrivial

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]

This PR/issue depends on:

• [Merged by Bors] - feat(CategoryTheory): group objects #21347
• [Merged by Bors] - feat(CategoryTheory): more API for ChosenFiniteProducts #21509
  By Dependent Issues (🤖). Happy coding!

[joelriou]

Thanks!

bors merge

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

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