lean_workbook_plus_29773

Proved

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

prove that $2\,{\frac {{a}^{2}-2\,ab+{b}^{2}+4}{ \left( {a}^{2}+1 \right) \left( {b}^{2}+1 \right) }}\geq 0$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_29773 : ∀ a b : ℝ, 2 * (a^2 - 2 * a * b + b^2 + 4) / (a^2 + 1) / (b^2 + 1) ≥ 0   :=  by sorry

Source