Any subset of (A × A) is called a binary relation to A. Here, (A × A) is the cartesian product of A with A.

Let A = {4, 5, 6) and R = {(4, 5), (6, 4), (5, 6)}

Here, R is a binary relation to A.

The domain of R is the set of first co-ordinates of R

Dom(R) = {4, 6, 5}

The range of R is the set of second co-ordinates of R

Range(R) = {5, 4, 6}