proposition: Lemma take_n_1_singleton (str : String) n ch (H : take n str ~= [ ch ]) : take 1 str ~= [ ch ].
proof: Proof. apply add_take_1_singleton in H. rewrite (take_take str 1 n) in H. destruct n; simpl min in H. { apply length_singleton in H; rewrite take_length in H. simpl in H; congruence. } { exact H. } 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