Let A and B be sets. (a) Prove that You may use Exercise 9(c). (b) Prove that...

Let A and B be sets.

(a) Prove that You may use Exercise 9(c).

(b) Prove that

(c) Show by example that set equality need not be the case in part (b). Under what conditions on A and B is

(d) Show that there are no sets A and B such that

Reference:

Let A, B, and C be sets. Prove that