by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)
By AM-GM inequality, 139a4b+131b4c+133c4a≥a3bc and 136a4b+135b4c+132c4a≥a2b2c and 135a4c+136b4a+132c4b≥a2b2c and 139a4c+133b4a+131c4b≥a3bc and 72a3c2+74b3a2+71c3b2≥a2b2c.
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_1849 : ∀ a b c : ℝ, (9 / 13 * a ^ 4 * b + 1 / 13 * b ^ 4 * c + 3 / 13 * c ^ 4 * a ≥ a ^ 3 * b * c ∧ 6 / 13 * a ^ 4 * b + 5 / 13 * b ^ 4 * c + 2 / 13 * c ^ 4 * a ≥ a ^ 2 * b ^ 2 * c ∧ 5 / 13 * a ^ 4 * c + 6 / 13 * b ^ 4 * a + 2 / 13 * c ^ 4 * b ≥ a ^ 2 * b ^ 2 * c ∧ 9 / 13 * a ^ 4 * c + 3 / 13 * b ^ 4 * a + 1 / 13 * c ^ 4 * b ≥ a ^ 3 * b * c ∧ 2 / 7 * a ^ 3 * c ^ 2 + 4 / 7 * b ^ 3 * a ^ 2 + 1 / 7 * c ^ 3 * b ^ 2 ≥ a ^ 2 * b ^ 2 * c) := by sorry