Lean is an open-source programming language and proof assistant that enables correct, maintainable, and formally verified code -- 'Grind' efficiently manages complex pattern matching and -- case analysis beyond standard tactics. example (x : Nat) : 0 < match x with | 0 => 1 | n+1 => x + n := by grind -- Automatically solves systems of linear inequalities. example (x y : Int) : 27 ≤ 11*x + 13*y → 1

