And Proof For Computer Science Fix | 6120a Discrete Mathematics

The union of two sets $A$ and $B$, denoted by $A \cup B$, is the set of all elements that are in $A$ or in $B$ or in both. The intersection of two sets $A$ and $B$, denoted by $A \cap B$, is the set of all elements that are in both $A$ and $B$.