MAYBE
MAYBE
TRS:
 {
                      mark(0()) -> active(0()),
                   mark(dbl(X)) -> active(dbl(mark(X))),
                     mark(s(X)) -> active(s(X)),
                    mark(nil()) -> active(nil()),
                  mark(dbls(X)) -> active(dbls(mark(X))),
             mark(cons(X1, X2)) -> active(cons(X1, X2)),
              mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
             mark(indx(X1, X2)) -> active(indx(mark(X1), X2)),
                  mark(from(X)) -> active(from(X)),
               active(dbl(0())) -> mark(0()),
              active(dbl(s(X))) -> mark(s(s(dbl(X)))),
            active(dbls(nil())) -> mark(nil()),
       active(dbls(cons(X, Y))) -> mark(cons(dbl(X), dbls(Y))),
   active(sel(0(), cons(X, Y))) -> mark(X),
  active(sel(s(X), cons(Y, Z))) -> mark(sel(X, Z)),
         active(indx(nil(), X)) -> mark(nil()),
    active(indx(cons(X, Y), Z)) -> mark(cons(sel(X, Z), indx(Y, Z))),
                active(from(X)) -> mark(cons(X, from(s(X)))),
                   dbl(mark(X)) -> dbl(X),
                 dbl(active(X)) -> dbl(X),
                     s(mark(X)) -> s(X),
                   s(active(X)) -> s(X),
                  dbls(mark(X)) -> dbls(X),
                dbls(active(X)) -> dbls(X),
             cons(X1, mark(X2)) -> cons(X1, X2),
           cons(X1, active(X2)) -> cons(X1, X2),
             cons(mark(X1), X2) -> cons(X1, X2),
           cons(active(X1), X2) -> cons(X1, X2),
              sel(X1, mark(X2)) -> sel(X1, X2),
            sel(X1, active(X2)) -> sel(X1, X2),
              sel(mark(X1), X2) -> sel(X1, X2),
            sel(active(X1), X2) -> sel(X1, X2),
             indx(X1, mark(X2)) -> indx(X1, X2),
           indx(X1, active(X2)) -> indx(X1, X2),
             indx(mark(X1), X2) -> indx(X1, X2),
           indx(active(X1), X2) -> indx(X1, X2),
                  from(mark(X)) -> from(X),
                from(active(X)) -> from(X)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
                        mark(0()) -> active(0()),
                     mark(dbl(X)) -> active(dbl(mark(X))),
                       mark(s(X)) -> active(s(X)),
                      mark(nil()) -> active(nil()),
                    mark(dbls(X)) -> active(dbls(mark(X))),
               mark(cons(X1, X2)) -> active(cons(X1, X2)),
                mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
               mark(indx(X1, X2)) -> active(indx(mark(X1), X2)),
                    mark(from(X)) -> active(from(X)),
                 active(dbl(0())) -> mark(0()),
                active(dbl(s(X))) -> mark(s(s(dbl(X)))),
              active(dbls(nil())) -> mark(nil()),
         active(dbls(cons(X, Y))) -> mark(cons(dbl(X), dbls(Y))),
     active(sel(0(), cons(X, Y))) -> mark(X),
    active(sel(s(X), cons(Y, Z))) -> mark(sel(X, Z)),
           active(indx(nil(), X)) -> mark(nil()),
      active(indx(cons(X, Y), Z)) -> mark(cons(sel(X, Z), indx(Y, Z))),
                  active(from(X)) -> mark(cons(X, from(s(X)))),
                     dbl(mark(X)) -> dbl(X),
                   dbl(active(X)) -> dbl(X),
                       s(mark(X)) -> s(X),
                     s(active(X)) -> s(X),
                    dbls(mark(X)) -> dbls(X),
                  dbls(active(X)) -> dbls(X),
               cons(X1, mark(X2)) -> cons(X1, X2),
             cons(X1, active(X2)) -> cons(X1, X2),
               cons(mark(X1), X2) -> cons(X1, X2),
             cons(active(X1), X2) -> cons(X1, X2),
                sel(X1, mark(X2)) -> sel(X1, X2),
              sel(X1, active(X2)) -> sel(X1, X2),
                sel(mark(X1), X2) -> sel(X1, X2),
              sel(active(X1), X2) -> sel(X1, X2),
               indx(X1, mark(X2)) -> indx(X1, X2),
             indx(X1, active(X2)) -> indx(X1, X2),
               indx(mark(X1), X2) -> indx(X1, X2),
             indx(active(X1), X2) -> indx(X1, X2),
                    from(mark(X)) -> from(X),
                  from(active(X)) -> from(X)
   }
  Fail