lean_workbook_plus_51654

Proved

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

Let $P(x,y)$ be the assertion $f(f(x)+y)=2x+f(f(y)-x)$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_51654 (f : ℤ → ℤ) (hf: f = fun x ↦ x) : ∀ x y, f (f x + y) = 2 * x + f (f y - x)   :=  by sorry

Source