lean_workbook_plus_3620

Disproved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

Prove the inequality $8(a+b+c)^3\ge 27(a+b)(b+c)(a+c)$ as a step to prove the original inequality.

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_3620 : ∀ a b c : ℝ, 8 * (a + b + c) ^ 3 ≥ 27 * (a + b) * (b + c) * (a + c)   :=  by sorry

Source