MAYBE
MAYBE
TRS:
 {
      U12(tt()) -> s(plus(N, M)),
      U11(tt()) -> U12(tt()),
  plus(N, s(M)) -> U11(tt()),
   plus(N, 0()) -> N,
      U22(tt()) -> plus(x(N, M), N),
      U21(tt()) -> U22(tt()),
     x(N, s(M)) -> U21(tt()),
      x(N, 0()) -> 0()
 }
 DUP: We consider a duplicating system.
  Trs:
   {
        U12(tt()) -> s(plus(N, M)),
        U11(tt()) -> U12(tt()),
    plus(N, s(M)) -> U11(tt()),
     plus(N, 0()) -> N,
        U22(tt()) -> plus(x(N, M), N),
        U21(tt()) -> U22(tt()),
       x(N, s(M)) -> U21(tt()),
        x(N, 0()) -> 0()
   }
  Fail