lean_workbook_plus_75350

Proved

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

Prove: If an integer $n$ is a sum of two square, then $2n$ is also a sum of two squares.

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_75350 (n : ℤ) : ∃ a b : ℤ, a^2 + b^2 = n → ∃ c d : ℤ, c^2 + d^2 = 2*n   :=  by sorry

Source