l3lab/ntp-mathlib huggingface dataset:
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    

Proof state:
case mk.mk
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
p₁ : ℕ
hp₁ : p₁ ∈ ps
p₂ : ℕ
hp₂ : p₂ ∈ ps
hne : { val := p₁, property := hp₁ } ≠ { val := p₂, property := hp₂ }
hp₁' : Fact (Nat.Prime p₁)
hp₂' : Fact (Nat.Prime p₂)
hne' : p₁ ≠ p₂
⊢ _root_.Disjoint ↑(P p₁) ↑(P p₂)

Next tactic:
apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  

Proof state:
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → (P : Sylow (↑p) G) → ↥↑P) ≃* G

Next tactic:
refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  

Proof state:
case refine'_1
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → (P : Sylow (↑p) G) → ↥↑P) ≃* ((p : { x // x ∈ ps }) → ↥(P ↑p))
case refine'_2
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → ↥(P ↑p)) ≃* G

Next tactic:
show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    

Proof state:
case refine'_1
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → (P : Sylow (↑p) G) → ↥P) ≃* ((p : { x // x ∈ ps }) → ↥(P ↑p))

Next tactic:
apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    

Proof state:
case refine'_1
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ (j : { x // x ∈ ps }) → ((P : Sylow (↑j) G) → ↥P) ≃* ↥↑(P ↑j)

Next tactic:
rintro ⟨p, hp⟩
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    

Proof state:
case refine'_1.mk
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
p : ℕ
hp : p ∈ ps
⊢ ((P : Sylow (↑{ val := p, property := hp }) G) → ↥P) ≃* ↥↑(P ↑{ val := p, property := hp })

Next tactic:
haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    

Proof state:
case refine'_1.mk
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
p : ℕ
hp : p ∈ ps
hp' : Fact (Nat.Prime p)
⊢ ((P : Sylow (↑{ val := p, property := hp }) G) → ↥P) ≃* ↥↑(P ↑{ val := p, property := hp })

Next tactic:
letI := unique_of_normal _ (hn (P p))
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    

Proof state:
case refine'_1.mk
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
p : ℕ
hp : p ∈ ps
hp' : Fact (Nat.Prime p)
this : Unique (Sylow p G) := unique_of_normal (P p) (_ : Normal ↑(P p))
⊢ ((P : Sylow (↑{ val := p, property := hp }) G) → ↥P) ≃* ↥↑(P ↑{ val := p, property := hp })

Next tactic:
apply MulEquiv.piUnique
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    apply MulEquiv.piUnique
  

Proof state:
case refine'_2
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → ↥(P ↑p)) ≃* G

Next tactic:
show (∀ p : ps, P p) ≃* G
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    apply MulEquiv.piUnique
  show (∀ p : ps, P p) ≃* G
  

Proof state:
case refine'_2
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ ((p : { x // x ∈ ps }) → ↥(P ↑p)) ≃* G

Next tactic:
apply MulEquiv.ofBijective (Subgroup.noncommPiCoprod hcomm)
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    apply MulEquiv.piUnique
  show (∀ p : ps, P p) ≃* G
  apply MulEquiv.ofBijective (Subgroup.noncommPiCoprod hcomm)
  

Proof state:
case refine'_2
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ Bijective ⇑(noncommPiCoprod hcomm)

Next tactic:
apply (bijective_iff_injective_and_card _).mpr
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    apply MulEquiv.piUnique
  show (∀ p : ps, P p) ≃* G
  apply MulEquiv.ofBijective (Subgroup.noncommPiCoprod hcomm)
  apply (bijective_iff_injective_and_card _).mpr
  

Proof state:
case refine'_2
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ Injective ⇑(noncommPiCoprod hcomm) ∧ Fintype.card ((i : { x // x ∈ ps }) → ↥↑(P ↑i)) = Fintype.card G

Next tactic:
constructor
/-- If all its Sylow subgroups are normal, then a finite group is isomorphic to the direct product
of these Sylow subgroups.
-/
noncomputable def directProductOfNormal [Fintype G]
    (hn : ∀ {p : ℕ} [Fact p.Prime] (P : Sylow p G), (↑P : Subgroup G).Normal) :
    (∀ p : (card G).primeFactors, ∀ P : Sylow p G, (↑P : Subgroup G)) ≃* G := by
  set ps := (Fintype.card G).primeFactors
  -- “The” Sylow subgroup for p
  let P : ∀ p, Sylow p G := default
  have hcomm : Pairwise fun p₁ p₂ : ps => ∀ x y : G, x ∈ P p₁ → y ∈ P p₂ → Commute x y := by
    rintro ⟨p₁, hp₁⟩ ⟨p₂, hp₂⟩ hne
    haveI hp₁' := Fact.mk (Nat.prime_of_mem_primeFactors hp₁)
    haveI hp₂' := Fact.mk (Nat.prime_of_mem_primeFactors hp₂)
    have hne' : p₁ ≠ p₂ := by simpa using hne
    apply Subgroup.commute_of_normal_of_disjoint _ _ (hn (P p₁)) (hn (P p₂))
    apply IsPGroup.disjoint_of_ne p₁ p₂ hne' _ _ (P p₁).isPGroup' (P p₂).isPGroup'
  refine' MulEquiv.trans (N := ∀ p : ps, P p) _ _
  -- There is only one Sylow subgroup for each p, so the inner product is trivial
  show (∀ p : ps, ∀ P : Sylow p G, P) ≃* ∀ p : ps, P p
  · -- here we need to help the elaborator with an explicit instantiation
    apply @MulEquiv.piCongrRight ps (fun p => ∀ P : Sylow p G, P) (fun p => P p) _ _
    rintro ⟨p, hp⟩
    haveI hp' := Fact.mk (Nat.prime_of_mem_primeFactors hp)
    letI := unique_of_normal _ (hn (P p))
    apply MulEquiv.piUnique
  show (∀ p : ps, P p) ≃* G
  apply MulEquiv.ofBijective (Subgroup.noncommPiCoprod hcomm)
  apply (bijective_iff_injective_and_card _).mpr
  constructor
  

Proof state:
case refine'_2.left
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ Injective ⇑(noncommPiCoprod hcomm)
case refine'_2.right
G : Type u
α : Type v
β : Type w
inst✝¹ : Group G
inst✝ : Fintype G
hn : ∀ {p : ℕ} [inst : Fact (Nat.Prime p)] (P : Sylow p G), Normal ↑P
ps : Finset ℕ := (Fintype.card G).primeFactors
P : (p : ℕ) → Sylow p G := default
hcomm : _root_.Pairwise fun p₁ p₂ => ∀ (x y : G), x ∈ P ↑p₁ → y ∈ P ↑p₂ → Commute x y
⊢ Fintype.card ((i : { x // x ∈ ps }) → ↥↑(P ↑i)) = Fintype.card G

Next tactic:
show Injective _