lean_workbook_plus_62152

Proved

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

Prove that $|x-y|+|x+y|\geq |x|+|y|$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_62152 (x y : ℝ) : |x-y|+|x+y| ≥ |x|+|y|   :=  by sorry

Source