MAYBE
MAYBE
TRS:
 {
          f(a(), x) -> f(b(), f(c(), x)),
  f(a(), f(b(), x)) -> f(b(), f(a(), x)),
  f(a(), f(c(), x)) -> f(c(), f(a(), x)),
  f(d(), f(c(), x)) -> f(d(), f(a(), x))
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
            f(a(), x) -> f(b(), f(c(), x)),
    f(a(), f(b(), x)) -> f(b(), f(a(), x)),
    f(a(), f(c(), x)) -> f(c(), f(a(), x)),
    f(d(), f(c(), x)) -> f(d(), f(a(), x))
   }
  Fail