diff --git a/thue-morse.v b/thue-morse.v
index b423ef0..74d4da6 100644
--- a/thue-morse.v
+++ b/thue-morse.v
@@ -1264,7 +1264,7 @@ Proof.
   apply H1 in H2. rewrite H2 at 1. easy. easy.
   rewrite nth_error_nth' with (d := false). easy.
   rewrite tm_size_power2. apply lt_split_bits.
-  assumption. apply Nat.pow_lt_mono_r. apply Nat.lt_1_2. assumption. assumption.
+  assumption. assumption. assumption.
 
   apply tm_step_stable. apply lt_split_bits.
   assumption. assumption. assumption.