MAYBE
MAYBE
TRS:
 {
          mark(cons(X1, X2)) -> cons(mark(X1), X2),
               mark(from(X)) -> a__from(mark(X)),
                  mark(s(X)) -> s(mark(X)),
                 mark(nil()) -> nil(),
                   mark(0()) -> 0(),
          mark(take(X1, X2)) -> a__take(mark(X1), mark(X2)),
               mark(head(X)) -> a__head(mark(X)),
                mark(2nd(X)) -> a__2nd(mark(X)),
           mark(sel(X1, X2)) -> a__sel(mark(X1), mark(X2)),
                  a__from(X) -> cons(mark(X), from(s(X))),
                  a__from(X) -> from(X),
                  a__head(X) -> head(X),
        a__head(cons(X, XS)) -> mark(X),
                   a__2nd(X) -> 2nd(X),
         a__2nd(cons(X, XS)) -> a__head(mark(XS)),
             a__take(X1, X2) -> take(X1, X2),
  a__take(s(N), cons(X, XS)) -> cons(mark(X), take(N, XS)),
            a__take(0(), XS) -> nil(),
              a__sel(X1, X2) -> sel(X1, X2),
   a__sel(s(N), cons(X, XS)) -> a__sel(mark(N), mark(XS)),
    a__sel(0(), cons(X, XS)) -> mark(X)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
            mark(cons(X1, X2)) -> cons(mark(X1), X2),
                 mark(from(X)) -> a__from(mark(X)),
                    mark(s(X)) -> s(mark(X)),
                   mark(nil()) -> nil(),
                     mark(0()) -> 0(),
            mark(take(X1, X2)) -> a__take(mark(X1), mark(X2)),
                 mark(head(X)) -> a__head(mark(X)),
                  mark(2nd(X)) -> a__2nd(mark(X)),
             mark(sel(X1, X2)) -> a__sel(mark(X1), mark(X2)),
                    a__from(X) -> cons(mark(X), from(s(X))),
                    a__from(X) -> from(X),
                    a__head(X) -> head(X),
          a__head(cons(X, XS)) -> mark(X),
                     a__2nd(X) -> 2nd(X),
           a__2nd(cons(X, XS)) -> a__head(mark(XS)),
               a__take(X1, X2) -> take(X1, X2),
    a__take(s(N), cons(X, XS)) -> cons(mark(X), take(N, XS)),
              a__take(0(), XS) -> nil(),
                a__sel(X1, X2) -> sel(X1, X2),
     a__sel(s(N), cons(X, XS)) -> a__sel(mark(N), mark(XS)),
      a__sel(0(), cons(X, XS)) -> mark(X)
   }
  Fail