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[Merged by Bors] - feat: tensor products of bialgebras #11977

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@101damnations 101damnations commented Apr 7, 2024

We define the data in the monoidal structure on bialgebras - e.g. the bialgebra instance on a tensor product of bialgebras, and the tensor product of two BialgHoms as a BialgHom. This is done by combining the corresponding API for coalgebras and algebras.


See #11974 and #11975 for explanation of the corresponding API for coalgebras.

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@leanprover-community-mathlib4-bot leanprover-community-mathlib4-bot added the blocked-by-other-PR This PR depends on another PR to Mathlib (this label is automatically managed by a bot) label Apr 7, 2024
@kbuzzard kbuzzard added awaiting-author A reviewer has asked the author a question or requested changes t-algebra Algebra (groups, rings, fields, etc) labels Oct 22, 2024
@101damnations 101damnations removed the awaiting-author A reviewer has asked the author a question or requested changes label Oct 23, 2024
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Thanks!

maintainer merge

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

@eric-wieser eric-wieser added the awaiting-author A reviewer has asked the author a question or requested changes label Oct 24, 2024
@101damnations 101damnations removed the awaiting-author A reviewer has asked the author a question or requested changes label Oct 27, 2024

theorem coalgebra_rid_eq_algebra_rid_apply (x) :
Coalgebra.TensorProduct.rid R A x = Algebra.TensorProduct.rid R R A x :=
congr($((TensorProduct.AlgebraTensorModule.rid_eq_rid R A).symm) x)
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The fact that this isn't rfl makes me think that one of the other two definitions is suboptimal? Did you already investigate how easy this is to fix? A TODO: make this defeq, which would involve [...] or similar is enough for this PR, as is "note: not possible to make defeq because [...`]

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It's not rfl because I didn't make Coalgebra.TensorProduct.rid heterobasic like the RHS is. I guess that's another drawback of my categorical approach, it's probably not the most amenable to adding heterobasic definitions. I've added a TODO comment.

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bors d+

Thanks!

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mathlib-bors bot commented Oct 27, 2024

✌️ 101damnations can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

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bors r+

mathlib-bors bot pushed a commit that referenced this pull request Oct 27, 2024
We define the data in the monoidal structure on bialgebras - e.g. the bialgebra instance on a tensor product of bialgebras, and the tensor product of two `BialgHom`s as a `BialgHom`. This is done by combining the corresponding API for coalgebras and algebras.



Co-authored-by: Amelia Livingston <[email protected]>
Co-authored-by: Eric Wieser <[email protected]>
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mathlib-bors bot commented Oct 27, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat: tensor products of bialgebras [Merged by Bors] - feat: tensor products of bialgebras Oct 27, 2024
@mathlib-bors mathlib-bors bot closed this Oct 27, 2024
@mathlib-bors mathlib-bors bot deleted the bialgtensorproduct branch October 27, 2024 19:58
mathlib-bors bot pushed a commit that referenced this pull request Feb 17, 2025
Monoidal category structure on bialgebras, using the definitions in `Mathlib.RingTheory.Bialgebra.TensorProduct` added in #11977 



Co-authored-by: Amelia Livingston <[email protected]>
Co-authored-by: Eric Wieser <[email protected]>
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9 participants