diff --git a/personoj/nat.lp b/personoj/nat.lp
index 7af7eb040d15e1ed74abfbfbfd6e1b7fd9448bf3..28a44499b65a88468f115a49f2d7f900c8be4826 100644
--- a/personoj/nat.lp
+++ b/personoj/nat.lp
@@ -1,5 +1,5 @@
 require open personoj.lhol personoj.logical;
-constant symbol Nat: TYPE;
+symbol Nat: TYPE;
 
 constant symbol zero: Nat;       builtin "0" ≔ zero;
 constant symbol succ: Nat → Nat; builtin "+1" ≔ succ;