1. For every set A, the Cartesian product Ø x A is empty. 2. For all sets A, B,C we have An (B-C) = (An B) - (ANC). 3. For all sets A, B,C we have AU (B-C) = (AUB) - (AUC). True 6. The set Q of rational numbers is countable. True 7. The Cantor set 2 is countable. True 4. If C is the image of a surjective map from A to B, then there is a bijection between A and C. False True 5. If D is the image of an injective map from A to B, then there is a bijection between A and D. False True False True False True False False False 8. There exists a well-ordering on the set R of countably infinite sequences of real numbers. True False

Fig: 1