Domain

 
A domain comprises a set of values. An example of a domain is the set of values a temperature sensor can deliver. In order to be able to talk unambiguously about this phenomenon, i.e. about this set of values, the designation TEMP is introduced as follows:

Example: Domain

The entry in the field Intention explains the phenomenon represented by this designation. The formal part of the definition specifies the set of possible values, in the example -40 to 70. Using the symbol < it can be specified whether the new domain is a subset of an already introduced domain. In the example the new domain TEMP is specified as a subset of INTEGER. This excludes that a temperature sensor delivers a real value, e.g. 4.11 $^\circ$C. It can deliver only 4 or 5$^\circ$C.

The following designations of domains do not have to be introduced explicitly, but can be used without being previously specified.

NAT

This designation represents the set of natural numbers.

INTEGER

This designation represents the set of integers.

REAL

This designation represents the set of real numbers.

TIME

This designation represents the set of all possible time points. This set is the set of the non-negative real numbers.

STRING

This designation represents the set of all finite words over the alphabet
$\{a,\ldots, z, A, \ldots, Z, \_, 0, \ldots, 9\}$.

The designations of domains are always written in capitals.