In order to illustrate the characteristics of a FOS, that are of interest in the context of Q-Calculus, we will use a simplified economic example of market analysis. Aspects of this example will be used throughout the book. FOS may be classified in several sorts that contain a certain type of objects. Each object has an identity, which distinguishes it from the other objects in the system. Inhabitants have for instance individual social security numbers.
Objects have furthermore observable properties.
Features of inhabitants are among others age, sex, education, civilian status, nationality and address. Each inhabitant has an individual value of the features. The person Meyer is 29 years old, male, Swiss, married and lives in St. The features of the individual objects impose a structure upon the corresponding set as well as its characteristics. The set of inhabitants may for instance be classified according to the personnel's age or sex in subsets of respectively young and old people or in men and women.