diff --git a/src/permutations.v b/src/permutations.v
index 78d4d88..5b7bca9 100644
--- a/src/permutations.v
+++ b/src/permutations.v
@@ -169,9 +169,8 @@ Proof.
   assert (incl ([length (l1++l2)]++l2++l1) (l1++[length (l1++l2)]++l2)).
   unfold incl. intro a. intro J. rewrite app_assoc in J.
   rewrite in_app_iff. rewrite in_app_iff in J. destruct J.
-  right. assumption. left. assumption.
-  apply incl_app_inv in H0. destruct H0. apply incl_app_inv in H1.
-  destruct H1.
+  right. assumption. left. assumption. apply incl_app_inv in H0.
+  destruct H0. apply incl_app_inv in H1. destruct H1.
   assert (incl (l1++l2) (l1 ++ [length (l1 ++ l2)] ++ l2)).
   apply incl_app; assumption.
   assert (incl ([length (l1++l2)]++l1++l2) (l1 ++ [length (l1 ++ l2)] ++ l2)).
@@ -184,11 +183,9 @@ Proof.
   apply incl_app. easy.
   apply perm_seq_1 in H. rewrite app_length in H. simpl in H.
   rewrite Nat.add_succ_r in H. rewrite seq_S in H. apply incl_app_inv in H.
-  destruct H. rewrite app_length at 1. assumption.
-  easy. apply Add_app.
-  unfold incl in I. unfold permutation.
-  intro k. intro. apply I. apply in_seq.
-  split. apply Nat.le_0_l. assumption.
+  destruct H. rewrite app_length at 1. assumption. easy. apply Add_app.
+  unfold incl in I. unfold permutation. intro k. intro.
+  apply I. apply in_seq. split. apply Nat.le_0_l. assumption.
 Qed.