MAYBE
MAYBE
TRS:
 {
               mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
              mark(fib1(X1, X2)) -> active(fib1(mark(X1), mark(X2))),
                      mark(s(X)) -> active(s(mark(X))),
                       mark(0()) -> active(0()),
                    mark(fib(X)) -> active(fib(mark(X))),
              mark(cons(X1, X2)) -> active(cons(mark(X1), X2)),
               mark(add(X1, X2)) -> active(add(mark(X1), mark(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),
              fib1(X1, mark(X2)) -> fib1(X1, X2),
            fib1(X1, active(X2)) -> fib1(X1, X2),
              fib1(mark(X1), X2) -> fib1(X1, X2),
            fib1(active(X1), X2) -> fib1(X1, X2),
                      s(mark(X)) -> s(X),
                    s(active(X)) -> s(X),
  active(sel(s(N), cons(X, XS))) -> mark(sel(N, XS)),
   active(sel(0(), cons(X, XS))) -> mark(X),
              active(fib1(X, Y)) -> mark(cons(X, fib1(Y, add(X, Y)))),
                  active(fib(N)) -> mark(sel(N, fib1(s(0()), s(0())))),
            active(add(s(X), Y)) -> mark(s(add(X, Y))),
             active(add(0(), X)) -> mark(X),
                    fib(mark(X)) -> fib(X),
                  fib(active(X)) -> fib(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),
               add(X1, mark(X2)) -> add(X1, X2),
             add(X1, active(X2)) -> add(X1, X2),
               add(mark(X1), X2) -> add(X1, X2),
             add(active(X1), X2) -> add(X1, X2)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
                 mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
                mark(fib1(X1, X2)) -> active(fib1(mark(X1), mark(X2))),
                        mark(s(X)) -> active(s(mark(X))),
                         mark(0()) -> active(0()),
                      mark(fib(X)) -> active(fib(mark(X))),
                mark(cons(X1, X2)) -> active(cons(mark(X1), X2)),
                 mark(add(X1, X2)) -> active(add(mark(X1), mark(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),
                fib1(X1, mark(X2)) -> fib1(X1, X2),
              fib1(X1, active(X2)) -> fib1(X1, X2),
                fib1(mark(X1), X2) -> fib1(X1, X2),
              fib1(active(X1), X2) -> fib1(X1, X2),
                        s(mark(X)) -> s(X),
                      s(active(X)) -> s(X),
    active(sel(s(N), cons(X, XS))) -> mark(sel(N, XS)),
     active(sel(0(), cons(X, XS))) -> mark(X),
                active(fib1(X, Y)) -> mark(cons(X, fib1(Y, add(X, Y)))),
                    active(fib(N)) -> mark(sel(N, fib1(s(0()), s(0())))),
              active(add(s(X), Y)) -> mark(s(add(X, Y))),
               active(add(0(), X)) -> mark(X),
                      fib(mark(X)) -> fib(X),
                    fib(active(X)) -> fib(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),
                 add(X1, mark(X2)) -> add(X1, X2),
               add(X1, active(X2)) -> add(X1, X2),
                 add(mark(X1), X2) -> add(X1, X2),
               add(active(X1), X2) -> add(X1, X2)
   }
  Fail