-- File: optlib/Optlib/Algorithm/GD/GradientDescentStronglyConvex.lean
Theorem statement:
theorem extracted_formal_statement_73.{u_1} {E : Type u_1} [inst : NormedAddCommGroup E] [inst_1 : InnerProductSpace ℝ E]
  [inst_2 : CompleteSpace E] {f : E → ℝ} {m : ℝ} {f' : E → E} {xm x₀ : E} {alg : Gradient_Descent_fix_stepsize f f' x₀}
  (hm : m > 0) (min : IsMinOn f univ xm)
  (step₂ : Gradient_Descent_fix_stepsize.a f f' x₀ ≤ 2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)))
  (hsc : StrongConvexOn univ m f) (this_1 : LipschitzWith (Gradient_Descent_fix_stepsize.l f f' x₀) f')
  (this_2 : ↑(Gradient_Descent_fix_stepsize.l f f' x₀) > 0) (k : ℕ)
  (this :
    inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)) ≥
      m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) *
          ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
        1 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) * ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2)
  (h_original_goal :
    -(2 * Gradient_Descent_fix_stepsize.a f f' x₀ *
          inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k))) ≤
      -(Gradient_Descent_fix_stepsize.a f f' x₀ *
              (2 * m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
            ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
          Gradient_Descent_fix_stepsize.a f f' x₀ * (2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
            ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2)) :
  Gradient_Descent_fix_stepsize.a f f' x₀ *
          (2 * m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
        ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
      Gradient_Descent_fix_stepsize.a f f' x₀ * (2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
        ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2 ≤
    2 * Gradient_Descent_fix_stepsize.a f f' x₀ *
      inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)) := sorry

Tactic state before:
case bc.bc
E : Type u_1
inst✝² : NormedAddCommGroup E
inst✝¹ : InnerProductSpace ℝ E
inst✝ : CompleteSpace E
f : E → ℝ
m : ℝ
f' : E → E
xm x₀ : E
alg : Gradient_Descent_fix_stepsize f f' x₀
hm : m > 0
min : IsMinOn f univ xm
step₂ : Gradient_Descent_fix_stepsize.a f f' x₀ ≤ 2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))
hsc : StrongConvexOn univ m f
this✝¹ : LipschitzWith (Gradient_Descent_fix_stepsize.l f f' x₀) f'
this✝ : ↑(Gradient_Descent_fix_stepsize.l f f' x₀) > 0
k : ℕ
this :
  inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)) ≥
    m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) *
        ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
      1 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) * ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2
⊢ -(2 * Gradient_Descent_fix_stepsize.a f f' x₀ *
        inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k))) ≤
    -(Gradient_Descent_fix_stepsize.a f f' x₀ *
            (2 * m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
          ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
        Gradient_Descent_fix_stepsize.a f f' x₀ * (2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
          ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2)

Tactic: apply neg_le_neg

Tactic state after:
[case bc.bc.a
 E : Type u_1
 inst✝² : NormedAddCommGroup E
 inst✝¹ : InnerProductSpace ℝ E
 inst✝ : CompleteSpace E
 f : E → ℝ
 m : ℝ
 f' : E → E
 xm x₀ : E
 alg : Gradient_Descent_fix_stepsize f f' x₀
 hm : m > 0
 min : IsMinOn f univ xm
 step₂ : Gradient_Descent_fix_stepsize.a f f' x₀ ≤ 2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))
 hsc : StrongConvexOn univ m f
 this✝¹ : LipschitzWith (Gradient_Descent_fix_stepsize.l f f' x₀) f'
 this✝ : ↑(Gradient_Descent_fix_stepsize.l f f' x₀) > 0
 k : ℕ
 this :
   inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)) ≥
     m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) *
         ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
       1 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀)) * ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2
 ⊢ Gradient_Descent_fix_stepsize.a f f' x₀ *
           (2 * m * ↑(Gradient_Descent_fix_stepsize.l f f' x₀) / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
         ‖Gradient_Descent_fix_stepsize.x f f' x₀ k - xm‖ ^ 2 +
       Gradient_Descent_fix_stepsize.a f f' x₀ * (2 / (m + ↑(Gradient_Descent_fix_stepsize.l f f' x₀))) *
         ‖f' (Gradient_Descent_fix_stepsize.x f f' x₀ k)‖ ^ 2 ≤
     2 * Gradient_Descent_fix_stepsize.a f f' x₀ *
       inner (Gradient_Descent_fix_stepsize.x f f' x₀ k - xm) (f' (Gradient_Descent_fix_stepsize.x f f' x₀ k))]

Premises used:
neg_le_neg : ∀ {α : Type u} [inst : OrderedAddCommGroup α] {a b : α}, a ≤ b → -b ≤ -a