Sets

Set theory questions usually involve basic definitions:

• Intersection ($A \cap B$): Elements found in both set A and set B.
• Union ($A \cup B$): All elements that are in set A, or in set B, or in both.
• Subsets: A set with $n$ elements has $2^n$ possible subsets.
• Proper Subsets: These are all subsets except the set itself, so there are $2^n - 1$ proper subsets.
• Power Set: The set of all subsets of a set. The number of elements in the power set of a set with $n$ elements is $2^n$.