TRS:
 {    fib(0()) -> 0(),
   fib(s(0())) -> s(0()),
  fib(s(s(x))) -> +(fib(s(x)), fib(x)),
     +(x, 0()) -> x,
    +(x, s(y)) -> s(+(x, y))}
 RPO Product:
  Quasi-Precedence:
  fib > +
  empty
  
  Qed


TRS:
 {    fib(0()) -> 0(),
   fib(s(0())) -> s(0()),
  fib(s(s(x))) -> +(fib(s(x)), fib(x)),
     +(x, 0()) -> x,
    +(x, s(y)) -> s(+(x, y))}
 Fail