lean_workbook_plus_79075

Disproved

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

prove that $\frac{1-a^2}{1+a^2}+ \frac{1-b^2}{1+b^2}+ \frac{1-c^2}{1+c^2}\ge 0$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_79075 : ∀ a b c : ℝ, (1 - a ^ 2) / (1 + a ^ 2) + (1 - b ^ 2) / (1 + b ^ 2) + (1 - c ^ 2) / (1 + c ^ 2) ≥ 0   :=  by sorry

Source