lean_workbook_plus_36970

Disproved

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

Prove the following inequality: $2(xy+yz+zx)-(x^2 +y^2 +z^2) \le 3 \ \ ;$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_36970 : ∀ x y z : ℝ, 2 * (x * y + y * z + z * x) - (x ^ 2 + y ^ 2 + z ^ 2) ≤ 3   :=  by sorry

Source