Update

thue-morse.v

@@ -23,16 +23,6 @@ Fixpoint tm_step (n: nat) : list bool :=
   end.
 
 (* ad hoc more or less general lemmas *)
-Lemma negb_double_map : forall (l : list bool),
-  map negb (map negb l) = l.
-Proof.
-  intro l.
-  induction l.
-  - reflexivity.
-  - simpl. rewrite IHl. replace (negb (negb a)) with (a).
-    reflexivity. rewrite negb_involutive. reflexivity.
-Qed.
-
 Lemma lt_split_bits : forall n m k j,
   0 < k -> j < 2^m -> k*2^m < 2^n -> k*2^m+j < 2^n.
 Proof.
@@ -297,7 +287,6 @@ Proof.
   - reflexivity.
   - simpl. rewrite tm_step_lemma. rewrite IHn. rewrite tm_morphism_concat.
     simpl in IHn. rewrite IHn. rewrite tm_build_negb. rewrite IHn.
-    rewrite map_app. rewrite negb_double_map.
     reflexivity.
 Qed.