MAYBE
MAYBE
TRS:
 {
         cons(mark(X1), X2) -> mark(cons(X1, X2)),
       cons(ok(X1), ok(X2)) -> ok(cons(X1, X2)),
       active(cons(X1, X2)) -> cons(active(X1), X2),
            active(zeros()) -> mark(cons(0(), zeros())),
            active(tail(X)) -> tail(active(X)),
  active(tail(cons(X, XS))) -> mark(XS),
              tail(mark(X)) -> mark(tail(X)),
                tail(ok(X)) -> ok(tail(X)),
       proper(cons(X1, X2)) -> cons(proper(X1), proper(X2)),
                proper(0()) -> ok(0()),
            proper(zeros()) -> ok(zeros()),
            proper(tail(X)) -> tail(proper(X)),
               top(mark(X)) -> top(proper(X)),
                 top(ok(X)) -> top(active(X))
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
           cons(mark(X1), X2) -> mark(cons(X1, X2)),
         cons(ok(X1), ok(X2)) -> ok(cons(X1, X2)),
         active(cons(X1, X2)) -> cons(active(X1), X2),
              active(zeros()) -> mark(cons(0(), zeros())),
              active(tail(X)) -> tail(active(X)),
    active(tail(cons(X, XS))) -> mark(XS),
                tail(mark(X)) -> mark(tail(X)),
                  tail(ok(X)) -> ok(tail(X)),
         proper(cons(X1, X2)) -> cons(proper(X1), proper(X2)),
                  proper(0()) -> ok(0()),
              proper(zeros()) -> ok(zeros()),
              proper(tail(X)) -> tail(proper(X)),
                 top(mark(X)) -> top(proper(X)),
                   top(ok(X)) -> top(active(X))
   }
  Fail