Question

Consider A = {"bob" , "cindy" , "hal", "steve"}

Define the P(A).

Use the "BIN Method," as described in class, define this power set.

Answer 1

To define the power set of A = {"bob", "cindy", "hal", "steve"} using the BIN method, proceed as follows. A '1' in the first position will correspond to choosing "bob", in the second position will correspond to choosing "cindy" and so on. Here is a table for the same:

0000	{}
0001	{"steve"}
0010	{"hal"}
0011	{"hal", "steve"}
0100	{"cindy"}
0101	{"cindy", "steve"}
0110	{"cindy", "hal"}
0111	{"cindy", "hal", "steve"}
1000	{"bob"}
1001	{"bob", "steve"}
1010	{"bob", "hal"}
1011	{"bob", "hal", "steve"}
1100	{"bob", "cindy"}
1101	{"bob", "cindy", "steve"}
1110	{"bob", "cindy", "hal"}
1111	{"bob", "cindy", "hal", "steve"}

The second column describes all the sets in P(A). Comment in case of any doubts.