proposition: Lemma get_drop {n str} : get n str = get 0 (drop n str).
proof: Proof. revert str; induction n; intros. { rewrite drop_0; reflexivity. } { rewrite !get_S, IHn. rewrite drop_drop. repeat (f_equal; []). omega. } Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Fiat.Common Fiat.Common.List.Operations Fiat.Common.List.ListFacts Fiat.Common.Le Fiat.Common.Tactics.SetoidSubst Fiat.Common.Tactics.IsClosed Fiat.Parsers.StringLike.Core Fiat.Common.UIP