lean_workbook_plus_15349

Proved

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

The possible quadratic residues in $\pmod {10}$ are: $0,1,4,5,6,9$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_15349 : {0, 1, 4, 5, 6, 9} = {n : ℕ | n < 10 ∧ ∃ k : ℕ, k < 10 ∧ n ≡ k ^ 2 [ZMOD 10]}   :=  by sorry

Source