TRS:
 {  exp(x, 0()) -> s(0()),
   exp(x, s(y)) -> *(x, exp(x, y)),
      *(0(), y) -> 0(),
     *(s(x), y) -> +(y, *(x, y)),
      -(0(), y) -> 0(),
      -(x, 0()) -> x,
  -(s(x), s(y)) -> -(x, y)}
 POP*:
  Precedence:
  * > +, 
  exp > *, 
  exp > s
  empty
  
Normal:
   pi(-) = [1,2], pi(*) = [1], pi(exp) = [1,2]
  
Safe:
   pi(+) = [1,2], pi(*) = [2], pi(s) = [1]
  
Predicative System:
   {    exp(x,0();) -> s(;0()),
      exp(x,s(;y);) -> *(x;exp(x,y;)),
           *(0();y) -> 0(),
         *(s(;x);y) -> +(;y,*(x;y)),
          -(0(),y;) -> 0(),
          -(x,0();) -> x,
    -(s(;x),s(;y);) -> -(x,y;)}
  Qed