diff --git a/arith.modal b/arith.modal
index 45deefd..c6bc774 100644
--- a/arith.modal
+++ b/arith.modal
@@ -326,15 +326,4 @@
 <> ((int1 (?h ?t))) ((int2 + (nat1 (?h ?t))))
 <> ((int2 ?s (N ?x))) ((Z (?s ?x)))
 
--- (str (pow (nat 17) (nat 17)))
-
-<> (a) ((N (1 (1 (1 ())))))
-<> (b) ((N (0 (1 (1 ())))))
-<> (c) ((N (0 (1 ()))))
-
--- (add a b)
--- (sum (a (b (c ()))))
--- (str (div (mul a b) c))
-
--- (mul (nat>neg (nat 13)) (nat>neg (nat 7)))
 (str (mul (int -133) (int 77)))