MAYBE
MAYBE
TRS:
 {
   adx(cons()) -> incr(cons()),
       zeros() -> cons(),
        nats() -> adx(zeros()),
  incr(cons()) -> cons(),
    hd(cons()) -> X,
    tl(cons()) -> Y
 }
 DUP: We consider a duplicating system.
  Trs:
   {
     adx(cons()) -> incr(cons()),
         zeros() -> cons(),
          nats() -> adx(zeros()),
    incr(cons()) -> cons(),
      hd(cons()) -> X,
      tl(cons()) -> Y
   }
  Fail