Personal computers, workstations, mainframes, file servers, and parallel machines make up the set of computers. Some objects in a given object set share the same properties as other objects in different object sets. There are student instructors, sport utility vehicles, and single parents. The symbols stand for union, intersection, mutual exclusion and partition. The union symbol means that the union of all the subsets is equal to the superset.
Intersection means that the subset is the intersection between two or more supersets.
Mutual exclusion means that an object can only be a member of excatly one subset. IS A or a colon and the name of the generalized superset. Usually, the colon is used as shorthand in other lexical OSA statements and expressions. A man, when married to a woman is called a husband. Not every man is married and only those who are married are called husbands.