lean_workbook_plus_32403

Proved

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

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

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_32403 (f : ℤ → ℤ) (hf: f = fun x ↦ x) : ∀ x y, f (f x + y) + f (f y + x) = f (2 * x + f (2 * y))   :=  by sorry

Source