Theorem: Sylow.conj_eq_normalizer_conj_of_mem_centralizer
File: Mathlib/GroupTheory/Sylow.lean

Proof steps:
state_before: p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
state_after: p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
tactic: have h1 : ↑P ≤ centralizer (zpowers x : Set G) := by rwa [le_centralizer_iff, zpowers_le]
state_before: p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
state_after: p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
tactic: have h2 : ↑(g • P) ≤ centralizer (zpowers x : Set G) := by
    rw [le_centralizer_iff, zpowers_le]
    rintro - ⟨z, hz, rfl⟩
    specialize hy z hz
    rwa [← mul_assoc, ← eq_mul_inv_iff_mul_eq, mul_assoc, mul_assoc, mul_assoc, ← mul_assoc,
      eq_inv_mul_iff_mul_eq, ← mul_assoc, ← mul_assoc] at hy
state_before: p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
state_after: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : h • (g • P).subtype h2 = P.subtype h1
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
tactic: obtain ⟨h, hh⟩ :=
    exists_smul_eq (centralizer (zpowers x : Set G)) ((g • P).subtype h2) (P.subtype h1)
state_before: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : h • (g • P).subtype h2 = P.subtype h1
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
state_after: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : ((↑h * g) • P).subtype ⋯ = P.subtype h1
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
tactic: simp_rw [Sylow.smul_subtype, Subgroup.smul_def, smul_smul] at hh
state_before: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : ((↑h * g) • P).subtype ⋯ = P.subtype h1
⊢ ∃ n ∈ (↑P).normalizer, g⁻¹ * x * g = n⁻¹ * x * n
state_after: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : ((↑h * g) • P).subtype ⋯ = P.subtype h1
⊢ g⁻¹ * x * g = (↑h * g)⁻¹ * x * (↑h * g)
tactic: refine ⟨h * g, Sylow.smul_eq_iff_mem_normalizer.mp (Sylow.subtype_injective hh), ?_⟩
state_before: case intro
p : ℕ
G : Type u_1
inst✝² : Group G
inst✝¹ : Fact (Nat.Prime p)
inst✝ : Finite (Sylow p G)
P : Sylow p G
x g : G
hx : x ∈ centralizer ↑P
hy : g⁻¹ * x * g ∈ centralizer ↑P
h1 : ↑P ≤ centralizer ↑(zpowers x)
h2 : ↑(g • P) ≤ centralizer ↑(zpowers x)
h : ↥(centralizer ↑(zpowers x))
hh : ((↑h * g) • P).subtype ⋯ = P.subtype h1
⊢ g⁻¹ * x * g = (↑h * g)⁻¹ * x * (↑h * g)
state_after: no goals
tactic: rw [← mul_assoc, Commute.right_comm (h.prop x (mem_zpowers x)), mul_inv_rev, inv_mul_cancel_right]