Less-than/more-than/at-least/at-most/differet-than/zero/one/two...

Keywords for indicating property cardinality restriction. They deal with allowed and defined number of listed properties (roles). They can be used to specify the number of individuals involved in the restriction. Indeed, classes can be defined depending on the number of listed properties. It is possible to declare a maximum, minimum or exact number of listed properties in domain. Cardinality restrictions can also be applied to the number of data attributes that a concept or instance has.

Keywords Meaning
less-than  <
more-than  >
at-most 
at-least 
different-than 

Examples

These examples show how to put restrictions on properties cardinality numbers - maximum, minimum or exact.

Example: The sentence defines the maximum number of allowed parents.
Every person is-a-child-of at-most two parents.
Example: Defines the minimum number of allowed parents.
Every person is-a-child-of at-least two parents.
Example: Defines the exact number of allowed parents.
Every person is-a-child-of two parents.
Example: Cardinality restriction about data attribute.
Every cat has-name at-most one (some string value).