Sets Over a Small Universe
James A. Storer · Birkhäuser Boston eBooks · 2002
So far, when looking at implementations of generic operations like MEMBER, INSERT, and DELETE, we have been assuming that the set of all possible elements (the ‘universe’) is much larger than the actual number of elements that will be stored. In fact, typically, the space of all possible items (e.g., names represented by strings of 25 characters) is larger than can possibly be stored.