lean_workbook_plus_48211

Proved

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

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

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_48211 (f : ℤ → ℤ) (hf: f = fun x ↦ x) : ∀ x y, f ((x - y) * f x) = f (y * f (x - y)) + (x - y) ^ 2   :=  by sorry

Source