Question: (a) List all the equivalence relations on the set {a}. How many are there altogether?
(b) Repeat (a) for the set {a, b}.
(c) [BB] Repeat (a) for the set {a, b, c}.
(d) Repeat (a) for the set {a, b, c, d}. (Remark: The number of partitions of a set of n elements grows rather rapidly. There are 52 partitions of a set of five elements, 203 partitions of a set of six elements, and 877 partitions of a set of seven elements.)