proposition: Lemma shiftl_negate_1_half x : x ≪ (-1) = x / 2.
proof: Proof. change (id (x ≪ (-1)) = id x / 2). now apply shiftl_negate_1_to_half. Qed.
imports: Coq.setoid_ring.Ring MathClasses.interfaces.abstract_algebra MathClasses.interfaces.naturals MathClasses.interfaces.integers MathClasses.interfaces.additional_operations MathClasses.interfaces.orders