proposition: Theorem beq_id_refl : forall id, true = beq_id id id.
proof: Proof. intros [n]. simpl. destruct (string_dec n n). - reflexivity. - destruct n0. reflexivity. Qed.
imports: Coq.Arith.Arith Coq.Bool.Bool Coq.Strings.String Coq.Logic.FunctionalExtensionality