lean_workbook_plus_20810

Proved

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

Prove that \n $4(ab+bc+ca)(b^2+bc+c^2)\le (b+c)^2(a+b+c)^2$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_20810 : ∀ a b c : ℝ, 4 * (a * b + b * c + c * a) * (b ^ 2 + b * c + c ^ 2) ≤ (b + c) ^ 2 * (a + b + c) ^ 2   :=  by sorry

Source