-cut neg n < neg n \to False.
-apply Hcut.apply H.simplify.apply not_le_Sn_n.
-cut pos n < pos n \to False.
-apply Hcut.apply H.simplify.apply not_le_Sn_n.
+cut (neg n < neg n \to False).
+apply Hcut.apply H.simplify.unfold lt.apply not_le_Sn_n.
+cut (pos n < pos n \to False).
+apply Hcut.apply H.simplify.unfold lt.apply not_le_Sn_n.