# Set theory - Equality

The equality relationship indicates that two sets are equal if they contain exactly the same elements. (There is no order among elements of a set.)

## Notation

Two sets are equal if they contain exactly the same elements. (There is no order among elements of a set.) $$\Large A = B$$

## Proof

A convenient way to prove that A and B are equal is to prove that each is a subset of the other. The proof often consists of two parts:

1. a proof that (ie A subset B) and
2. a proof that (ie B subset A)