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[Merged by Bors] - feat(Order/Category): partial orders with order embeddings as morphisms#30693

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[Merged by Bors] - feat(Order/Category): partial orders with order embeddings as morphisms#30693
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joelriou:partial-order-embeddings

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@joelriou joelriou commented Oct 19, 2025 •
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This category will be relevant in the study of accessible categories. I am making Johan Commelin a co-author as the new file PartOrdEmb.lean is essentially a copy-paste of PartOrd.Lean.

Co-authored-by: Johan Commelin johan@commelin.net

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@joelriou joelriou added the t-order Order theory label Oct 19, 2025
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github-actions bot commented Oct 19, 2025 •
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PR summary 2c2d756603

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference
Mathlib.Order.Category.PartOrdEmb (new file) 462

Declarations diff

+ Hom
+ Hom.Simps.hom
+ Hom.hom
+ Hom.injective
+ Iso.mk
+ PartOrdEmb
+ coe_comp
+ coe_id
+ coe_of
+ comp_apply
+ dual
+ dualEquiv
+ ext
+ forget_map
+ hasForgetToPartOrd
+ hom_comp
+ hom_ext
+ hom_id
+ hom_inv_apply
+ hom_ofHom
+ id_apply
+ instance : Category PartOrdEmb.{u}
+ instance : CoeSort PartOrdEmb (Type _)
+ instance : ConcreteCategory PartOrdEmb (· ↪o ·)
+ inv_hom_apply
+ of
+ ofHom
+ ofHom_apply
+ ofHom_comp
+ ofHom_hom
+ ofHom_id
+ partOrdEmb_dual_comp_forget_to_pardOrd

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).

joelriou
joelriou commented Oct 19, 2025
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kim-em
kim-em reviewed Oct 29, 2025
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Mathlib/Order/Category/PartOrdEmb.lean
Comment on lines +139 to +141
instance hasForgetToPartOrd : HasForget₂ PartOrdEmb PartOrd where
forget₂.obj X := .of X
forget₂.map f := PartOrd.ofHom f.hom
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@kim-em kim-em Oct 29, 2025

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Do we have the subcategory of monomorphisms somewhere? Can we identify this with that?

I'm happy for you to proceed if that either is too big a detour, or there's a reason you think it wouldn't be helpful.

bors d+

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Actually, monomorphisms correspond to injective maps, but there are some injective monotone maps between partial orders that are not order embeddings (consider the identity of Fin 2 where there is the usual order on the target but in the source 0 and 1 are not comparable).

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mathlib-bors bot commented Oct 29, 2025

✌️ joelriou can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

@ghost ghost added the delegated This pull request has been delegated to the PR author (or occasionally another non-maintainer). label Oct 29, 2025
@joelriou joelriou added the awaiting-author A reviewer has asked the author a question or requested changes. label Oct 29, 2025
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joelriou commented Oct 29, 2025

Thanks!

bors merge

@joelriou joelriou removed the awaiting-author A reviewer has asked the author a question or requested changes. label Oct 29, 2025
@ghost ghost added the ready-to-merge This PR has been sent to bors. label Oct 29, 2025
mathlib-bors bot pushed a commit that referenced this pull request Oct 29, 2025
@joelriou @jcommelin
feat(Order/Category): partial orders with order embeddings as morphis…
fb07d79 
…ms (#30693)

This category will be relevant in the study of accessible categories. I am making Johan Commelin a co-author as the new file `PartOrdEmb.lean` is essentially a copy-paste of `PartOrd.Lean`.

Co-authored-by: Johan Commelin <johan@commelin.net>
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mathlib-bors bot commented Oct 29, 2025

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat(Order/Category): partial orders with order embeddings as morphisms [Merged by Bors] - feat(Order/Category): partial orders with order embeddings as morphisms Oct 29, 2025
@mathlib-bors mathlib-bors bot closed this Oct 29, 2025
BeibeiX0 pushed a commit to BeibeiX0/mathlib4 that referenced this pull request Nov 7, 2025
@joelriou @jcommelin @BeibeiX0
feat(Order/Category): partial orders with order embeddings as morphis…
247cdb3 
…ms (leanprover-community#30693)

This category will be relevant in the study of accessible categories. I am making Johan Commelin a co-author as the new file `PartOrdEmb.lean` is essentially a copy-paste of `PartOrd.Lean`.

Co-authored-by: Johan Commelin <johan@commelin.net>
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