lean_workbook_plus_51667

Disproved

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

$\sum \frac{a}{b+c} \ge \sum \frac{2ab}{(c+b)(a+c)}$ $<=>a^3+b^3+c^3+3abc \ge \sum ab(a+b)$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_51667 : ∀ a b c : ℝ, a^3 + b^3 + c^3 + 3 * a * b * c ≥ a * b * (a + b) + b * c * (b + c) + c * a * (c + a)   :=  by sorry

Source