Complement of a Set

The COMPLEMENT of a set A, denoted $A'$ or $A^c$, is defined as $A' = \{x/x\in U, x\notin A\}$ — that is, the set of all elements of the universal set U that are NOT in A. For example, let $X=\{0,1,2,3,4,5,6,7,8\}$ be the universal set and $A=\{2,4,6,8\}$; then the complement of A is $A'=\{0,1,3,5,7\}$ — every element of X that isn't in A. …