Mathematical definitions are expected to be complete, in that if I define an A to be a pair of a B and a C, with no further restrictions, I will accept any such

Mathematical definitions are expected to be complete, in that if I define an A to be a pair of a B and a C, with no further restrictions, I will accept any such pair as an A. As an example of a more abstract way of looking at programming, take a look at domain theory. A domain is a set with a relation on it. But opposed to the current topic, there are more restrictions making a beautiful theory, capturing things such as lazy evaluation.