YES

Problem:
 f(0(x1)) -> s(0(x1))
 d(0(x1)) -> 0(x1)
 d(s(x1)) -> s(s(d(x1)))
 f(s(x1)) -> d(f(x1))

Proof:
 WPO Processor:
  algebra: Sum
  weight function:
   w0 = 0
   w(f) = 1
   w(d) = w(s) = w(0) = 0
  status function:
   st(d) = st(s) = st(f) = st(0) = [0]
  precedence:
   f > d > s ~ 0
  problem:
   
  Qed