(CONDITIONTYPE ORIENTED)
(VAR n r x xs y q)
(RULES
  filter(n,r,nil) -> pair(mo,nil)
  filter(n,r,cons(x,xs)) -> pair(x,xs) | eq(div(x,n),pair(q,r)) == true
  filter(n,r,cons(x,xs)) -> pair(y,cons(x,ys)) | filter(n,r,xs) == pair(y,ys), eq(div(x,n),pair(q,r)) == false
)(COMMENT
  \cite{SMI95}, p. 13
  doi: 10.1007/3-540-59200-8_56
)