2-2A #2 Rewrite the following using mathematical symbols:
a. P is equal to the set containing a, b, c, and d.
b. The set consisting of the elements 1 and 2 is a proper
subset of {1, 2, 3, 4}
c. The set consisting of the elements 0 and 1 is not a
subset of {1, 2, 3, 4}
d. 0 is not an element of the empty set.