lean_workbook_plus_6201

Proved

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

Let $a,b$ be real numbers. Prove that $2(a^2+1)(b^2+1)\ge (a+1)(b+1)(ab+1)$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_6201 (a b : ℝ) : 2 * (a ^ 2 + 1) * (b ^ 2 + 1) ≥ (a + 1) * (b + 1) * (a * b + 1)   :=  by sorry

Source