lean_workbook_plus_28605

Proved

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

Let $x$ and $y$ be real numbers such that $x^2 + y^2 - 1 < xy$ . Prove that $x + y - |x - y| < 2$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_28605 : ∀ x y : ℝ, x^2 + y^2 - 1 < x * y → x + y - |x - y| < 2   :=  by sorry

Source