Set Equality

Abstract

• Given Set A and B. The Cardinality of a Set must be the same
• First way to prove:

$$A=B\leftrightarrow (A\subseteq B)\wedge (B\subseteq A)$$

• Second way to prove:

$$A=B\leftrightarrow \forall x(x\in A\leftrightarrow x\in B)$$