lean_workbook_plus_76348

Proved

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

Prove that $x^2(1+y^2)(1+z^2)+y^2z^2+2\ge 2x(y+z)+2yz$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_76348 (x y z : ℝ) : x ^ 2 * (1 + y ^ 2) * (1 + z ^ 2) + y ^ 2 * z ^ 2 + 2 ≥ 2 * x * (y + z) + 2 * y * z   :=  by sorry

Source