MAYBE
Trs:
 {        length(cons(h, t)) -> s(length(t)),
               length(nil()) -> 0(),
                 leq(0(), m) -> true(),
              leq(s(n), 0()) -> false(),
             leq(s(n), s(m)) -> leq(n, m),
       if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))),
      if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))),
            fstsplit(0(), x) -> nil(),
  fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)),
       fstsplit(s(n), nil()) -> nil(),
           empty(cons(h, t)) -> false(),
                empty(nil()) -> true(),
      if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m),
      if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m),
      map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)),
           map_f(pid, nil()) -> nil(),
          app(cons(h, t), x) -> cons(h, app(t, x)),
               app(nil(), x) -> x,
            sndsplit(0(), x) -> x,
  sndsplit(s(n), cons(h, t)) -> sndsplit(n, t),
       sndsplit(s(n), nil()) -> nil(),
           process(store, m) -> if1(store, m, leq(m, length(store)))}
 Comment:
  We consider a duplicating trs.
  FAIL:
   Open