(sort Math)
(constructor Num (i64) Math)
(relation myrel (i64))
(relation shouldappear ())
(relation shouldnotappear ())
(myrel 1)
(myrel 2)
(rule ((= (myrel 1) (myrel 1)))
((shouldappear)))
(rule ((= (myrel 1) (myrel 2)))
((shouldnotappear)))
(run 1)
(check (shouldappear))
(fail (check (shouldnotappear)))