ordered pair
if 
and 
are any objects (possibly equal), we define the ordered pair 
to be a new object, consisting of as its first component and as its second component. two ordered pairs and 
are considered equal if and only if both their components match, i.e.,
[cite:;taken from @tao_analysis_1 definition 3.5.1]
and are any objects (possibly equal), we define the ordered pair to be a new object, consisting of as its first component and as its second component. two ordered pairs and are considered equal if and only if both their components match, i.e.,[cite:;taken from @tao_analysis_1 definition 3.5.1]