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[Merged by Bors] - feat(RepresentationTheory/*): representations on Finsupp#21732

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[Merged by Bors] - feat(RepresentationTheory/*): representations on Finsupp#21732
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@101damnations 101damnations commented Feb 11, 2025

Given a type α and a representation A, this PR defines Rep.finsupp, the representation defined pointwise on α →₀ A, and specializes this to Rep.free, when A = leftRegular k G.

We define Rep.freeLiftLEquiv α A, the k-linear equivalence between functions α → A and representation morphisms Rep.free k G α ⟶ A.

We also define representation isomorphisms (α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B) given representations A and B, and finally k[G] ⊗ (α →₀ k) ≅ free k G α where α →₀ k is equipped with the trivial representation.


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mathlib-bors bot pushed a commit that referenced this pull request May 30, 2025
Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
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mathlib-bors bot commented May 30, 2025

Canceled.

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mathlib-bors bot pushed a commit that referenced this pull request May 30, 2025
Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
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mathlib-bors bot commented May 30, 2025

Pull request successfully merged into master.

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@mathlib-bors mathlib-bors bot changed the title feat(RepresentationTheory/*): representations on Finsupp [Merged by Bors] - feat(RepresentationTheory/*): representations on Finsupp May 30, 2025
@mathlib-bors mathlib-bors bot closed this May 30, 2025
@mathlib-bors mathlib-bors bot deleted the repfinsupp branch May 30, 2025 11:26
bwehlin pushed a commit to bwehlin/mathlib4 that referenced this pull request May 31, 2025
…]` to `Finsupp.finsuppProd(L)Equiv` (leanprover-community#23021)

This was raised by @Whysoserioushah regarding leanprover-community#21732. We add `Finsupp.uncurry_apply`, which simplifies `Finsupp.uncurry` applied to a term of a product type `xy : α × β`, to prevent `Basis.smulTower_repr` breaking. However, we don't tag this with `@[simp]`; there is already a `@[simp]` tag on the less eager `Finsupp.uncurry_apply_pair`, which applies to a pair of terms `x : α`, `y : β`.
bwehlin pushed a commit to bwehlin/mathlib4 that referenced this pull request May 31, 2025
…r-community#21732)

Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
joelriou pushed a commit that referenced this pull request Jun 8, 2025
Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
TOMILO87 pushed a commit that referenced this pull request Jun 8, 2025
Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
This was referenced Jun 14, 2025
callesonne pushed a commit to callesonne/mathlib4 that referenced this pull request Jul 24, 2025
…r-community#21732)

Given a type `α` and a representation `A`, this PR defines `Rep.finsupp`, the representation defined pointwise on `α →₀ A`, and specializes this to `Rep.free`, when `A = leftRegular k G`.

We define `Rep.freeLiftLEquiv α A`, the `k`-linear equivalence between functions `α → A` and representation morphisms `Rep.free k G α ⟶ A`.

We also define representation isomorphisms `(α →₀ A) ⊗ B ≅ (A ⊗ B) →₀ α ≅ A ⊗ (α →₀ B)` given representations `A` and `B`, and finally `k[G] ⊗ (α →₀ k) ≅ free k G α` where `α →₀ k` is equipped with the trivial representation.



Co-authored-by: Amelia Livingston <40745104+101damnations@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Co-authored-by: 101damnations <al3717@ic.ac.uk>
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