1.if A is a set, give two subsets of A.
2. (a) if A and B are finite sets and A is a proper subset of B, what can u say about the cardinalities of the two sets??
(b) if the cardinality of A is less than the cardinality of B, does it follow that A is a proper subset of B??
3.if A and B have the same cardinality, does it follow that A=B? Explain.