“…Then α is an orbit invariant on S, while S is not a scrambled set of f . However, in [12] it is shown that when we restrict our discussions to shift maps σ : Σ(N) → Σ(N), N ≥ 2, together with η(x, y) ≡ 1, x, y ∈ S, the existence of an orbit invariant on S is also a sufficient condition for S ⊆ Σ(N) to be a scrambled set of σ . Where η(·, ·) : S × S → [0, 1] is defined as:…”