3. For each of the following relations on the set Z of integers,
determine if it is reflexive, symmetric, antisymmetric, or
transitive. On the basis of these properties, state whether or not
it is an equivalence relation or a partial order.
(a) R = {(a, b) ∈ Z 2 ∶ a 2 = b 2 }.
(b) S = {(a, b) ∈ Z 2 ∶ ∣a − b∣ ≤ 1}.