Theorem: Submodule.LinearDisjoint.linearIndependent_mul_of_flat_right
File: Mathlib/LinearAlgebra/LinearDisjoint.lean

Proof steps:
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : LinearIndependent R m
hn : LinearIndependent R n
⊢ LinearIndependent R fun i => ↑(m i.1) * ↑(n i.2)
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: rw [LinearIndependent, LinearMap.ker_eq_bot] at hm hn ⊢
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: let i0 := (finsuppTensorFinsupp' R κ ι).symm
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: let i1 := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι N R n)
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: let i2 := LinearMap.rTensor N (Finsupp.total κ M R m)
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: let i := mulMap M N ∘ₗ i2 ∘ₗ i1 ∘ₗ i0.toLinearMap
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: have h1 : Function.Injective i1 := Module.Flat.lTensor_preserves_injective_linearMap _ hn
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: have h2 : Function.Injective i2 := Module.Flat.rTensor_preserves_injective_linearMap _ hm
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
h : Function.Injective ⇑i
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: have h : Function.Injective i := H.injective.comp h2 |>.comp h1 |>.comp i0.injective
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
h : Function.Injective ⇑i
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
h : Function.Injective ⇑i
this : i = Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
tactic: have : i = Finsupp.total (κ × ι) S R fun i ↦ (m i.1).1 * (n i.2).1 := by
    ext x
    simp [i, i0, i1, i2, finsuppTensorFinsupp'_symm_single_eq_single_one_tmul]
state_before: R : Type u
S : Type v
inst✝³ : CommRing R
inst✝² : Ring S
inst✝¹ : Algebra R S
M N : Submodule R S
H : M.LinearDisjoint N
inst✝ : Module.Flat R ↥N
κ : Type u_1
ι : Type u_2
m : κ → ↥M
n : ι → ↥N
hm : Function.Injective ⇑(Finsupp.total κ (↥M) R m)
hn : Function.Injective ⇑(Finsupp.total ι (↥N) R n)
i0 : (κ × ι →₀ R) ≃ₗ[R] (κ →₀ R) ⊗[R] (ι →₀ R) := (finsuppTensorFinsupp' R κ ι).symm
i1 : (κ →₀ R) ⊗[R] (ι →₀ R) →ₗ[R] (κ →₀ R) ⊗[R] ↥N := LinearMap.lTensor (κ →₀ R) (Finsupp.total ι (↥N) R n)
i2 : (κ →₀ R) ⊗[R] ↥N →ₗ[R] ↥M ⊗[R] ↥N := LinearMap.rTensor (↥N) (Finsupp.total κ (↥M) R m)
i : (κ × ι →₀ R) →ₗ[R] S := M.mulMap N ∘ₗ i2 ∘ₗ i1 ∘ₗ ↑i0
h1 : Function.Injective ⇑i1
h2 : Function.Injective ⇑i2
h : Function.Injective ⇑i
this : i = Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2)
⊢ Function.Injective ⇑(Finsupp.total (κ × ι) S R fun i => ↑(m i.1) * ↑(n i.2))
state_after: no goals
tactic: rwa [this] at h