TRS:
 {    fib(0()) -> 0(),
   fib(s(0())) -> s(0()),
  fib(s(s(x))) -> +(fib(s(x)), fib(x))}
 MPO:
  Prec:
   fib > +
   empty
  Strict:
   {}
   Weak:
    {}
  Qed