(iii)
E and O are disjoint and Z = E ∪ O The subset E is called the equivalence class containing zero and is denoted by
[0] Similarly, O is the equivalence class containing 1 and is denoted by [1] Note that
[0] ≠ [1], [0] = [2r] and [1] = [2r + 1], r ∈ Z