lean_workbook_plus_59937

Proved

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

Prove that $\left(a+b+c+d\right)^2\geq 4\left(a+b\right)\left(c+d\right)$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_59937 : ∀ a b c d : ℝ, (a + b + c + d) ^ 2 ≥ 4 * (a + b) * (c + d)   :=  by sorry

Source