have h3 : b ≤ c := le_of_not_le Hcb
case inr
a b c : ℝ
ha : 0 ≤ a
hb : 0 ≤ b
hc : 0 ≤ c
h1 :
  ∀ {a b c : ℝ},
    0 ≤ a → 0 ≤ b → 0 ≤ c → c ≤ b → 0 ≤ a * (a - b) * (a - c) + b * (b - a) * (b - c) + c * (c - a) * (c - b)
Hcb : ¬c ≤ b
⊢ 0 ≤ a * (a - b) * (a - c) + b * (b - a) * (b - c) + c * (c - a) * (c - b)
case inr
a b c : ℝ
ha : 0 ≤ a
hb : 0 ≤ b
hc : 0 ≤ c
h1 :
  ∀ {a b c : ℝ},
    0 ≤ a → 0 ≤ b → 0 ≤ c → c ≤ b → 0 ≤ a * (a - b) * (a - c) + b * (b - a) * (b - c) + c * (c - a) * (c - b)
Hcb : ¬c ≤ b
h3 : b ≤ c
⊢ 0 ≤ a * (a - b) * (a - c) + b * (b - a) * (b - c) + c * (c - a) * (c - b)