theorem extracted_formal_statement_337.{u_3, u_2, u_1} {E₁ : Type u_1} {E₂ : Type u_2} {F : Type u_3}
  [inst : NormedAddCommGroup E₁] [inst_1 : InnerProductSpace ℝ E₁] [inst_2 : FiniteDimensional ℝ E₁]
  [inst_3 : NormedAddCommGroup E₂] [inst_4 : InnerProductSpace ℝ E₂] [inst_5 : FiniteDimensional ℝ E₂]
  [inst_6 : NormedAddCommGroup F] [inst_7 : InnerProductSpace ℝ F] [inst_8 : FiniteDimensional ℝ F]
  {admm : ADMM E₁ E₂ F} {admm_kkt : Existance_of_kkt admm} [inst_9 : Setting E₁ E₂ F admm admm_kkt]
  (htau : 1 < ADMM.τ E₁ E₂ F) (n : ℕ+) :
  let x_diff := ADMM.x₂ E₁ F (↑n + 1) - ADMM.x₂ E₁ F ↑n;
  let r_n := (OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂;
  2 * M (n + 1) = (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F * (-2 * ⟪(OptProblem.A₂ E₁) x_diff, r_n⟫_ℝ) →
    (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F * (-2 * ⟪(OptProblem.A₂ E₁) x_diff, r_n⟫_ℝ) ≤
        (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F *
          (ADMM.τ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
            1 / ADMM.τ E₁ E₂ F *
              ‖(OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂‖ ^ 2) →
      (ADMM.τ E₁ E₂ F * ADMM.τ E₁ E₂ F - 1 * ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
          (ADMM.τ E₁ E₂ F * (1 / ADMM.τ E₁ E₂ F) - 1 * (1 / ADMM.τ E₁ E₂ F)) * ADMM.ρ E₁ E₂ F *
            ‖(OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂‖ ^ 2 =
        (ADMM.τ E₁ E₂ F ^ 2 - ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
          (1 - 1 / ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖r_n‖ ^ 2 := sorry

State before:
E₁ : Type u_1
E₂ : Type u_2
F : Type u_3
inst✝⁹ : NormedAddCommGroup E₁
inst✝⁸ : InnerProductSpace ℝ E₁
inst✝⁷ : FiniteDimensional ℝ E₁
inst✝⁶ : NormedAddCommGroup E₂
inst✝⁵ : InnerProductSpace ℝ E₂
inst✝⁴ : FiniteDimensional ℝ E₂
inst✝³ : NormedAddCommGroup F
inst✝² : InnerProductSpace ℝ F
inst✝¹ : FiniteDimensional ℝ F
admm : ADMM E₁ E₂ F
admm_kkt : Existance_of_kkt admm
inst✝ : Setting E₁ E₂ F admm admm_kkt
htau : 1 < ADMM.τ E₁ E₂ F
n : ℕ+
x_diff : E₂ := ADMM.x₂ E₁ F (↑n + 1) - ADMM.x₂ E₁ F ↑n
r_n : F := (OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂
r_n_1 : F :=
  (OptProblem.A₁ E₂) (ADMM.x₁ E₂ F (↑n + 1)) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F (↑n + 1)) - OptProblem.b E₁ E₂
e_sum : F := (OptProblem.A₁ E₂) (e₁ ↑n) + (OptProblem.A₂ E₁) (e₂ ↑n)
e_sum_1 : F := (OptProblem.A₁ E₂) (e₁ (↑n + 1)) + (OptProblem.A₂ E₁) (e₂ (↑n + 1))
a₁ : ℝ := 1 / (ADMM.τ E₁ E₂ F * ADMM.ρ E₁ E₂ F) * ‖ey ↑n‖ ^ 2
a₂ : ℝ := 1 / (ADMM.τ E₁ E₂ F * ADMM.ρ E₁ E₂ F) * ‖ey (↑n + 1)‖ ^ 2
b₁ : ℝ := ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) (e₂ ↑n)‖ ^ 2
b₂ : ℝ := ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) (e₂ (↑n + 1))‖ ^ 2
c₁ : ℝ := (1 - 1 / ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖e_sum‖ ^ 2
c₂ : ℝ := (1 - 1 / ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖e_sum_1‖ ^ 2
d₁ : ℝ := (1 + ADMM.τ E₁ E₂ F - ADMM.τ E₁ E₂ F ^ 2) * ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2
d₂ : ℝ := (1 + 1 / ADMM.τ E₁ E₂ F - ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖r_n_1‖ ^ 2
h1 : 2 * M (n + 1) = (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F * (-2 * ⟪(OptProblem.A₂ E₁) x_diff, r_n⟫_ℝ)
h2 :
  (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F * (-2 * ⟪(OptProblem.A₂ E₁) x_diff, r_n⟫_ℝ) ≤
    (ADMM.τ E₁ E₂ F - 1) * ADMM.ρ E₁ E₂ F *
      (ADMM.τ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
        1 / ADMM.τ E₁ E₂ F *
          ‖(OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂‖ ^ 2)
⊢ (ADMM.τ E₁ E₂ F * ADMM.τ E₁ E₂ F - 1 * ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
      (ADMM.τ E₁ E₂ F * (1 / ADMM.τ E₁ E₂ F) - 1 * (1 / ADMM.τ E₁ E₂ F)) * ADMM.ρ E₁ E₂ F *
        ‖(OptProblem.A₁ E₂) (ADMM.x₁ E₂ F ↑n) + (OptProblem.A₂ E₁) (ADMM.x₂ E₁ F ↑n) - OptProblem.b E₁ E₂‖ ^ 2 =
    (ADMM.τ E₁ E₂ F ^ 2 - ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖(OptProblem.A₂ E₁) x_diff‖ ^ 2 +
      (1 - 1 / ADMM.τ E₁ E₂ F) * ADMM.ρ E₁ E₂ F * ‖r_n‖ ^ 2

Tactic: rw [pow_two τ, one_mul, mul_one_div_cancel (by linarith [htau]), one_mul]

State after:

Relevant lemmas:
pow_two : ∀ {M : Type u_2} [inst : Monoid M] (a : M), a ^ 2 = a * a
mul_one_div_cancel : ∀ {G₀ : Type u_3} [inst : GroupWithZero G₀] {a : G₀}, a ≠ 0 → a * (1 / a) = 1
one_mul : ∀ {M : Type u} [inst : MulOneClass M] (a : M), 1 * a = a