lean_workbook_plus_27167

Proved

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

For $a,b,c,d$ , show that $a^4+b^4+c^4+d^4\geq a^2bc+b^2cd+c^2da+d^2ab$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_27167 : ∀ a b c d : ℝ, a^4+b^4+c^4+d^4 ≥ a^2*b*c + b^2*c*d + c^2*d*a + d^2*a*b   :=  by sorry

Source