Database Reference
In-Depth Information
If several classes are mutually disjoint, OWL 2 has introduced an additional prop-
erty
owl:disjointClasses
, which avoids the need to use
owl:disjointWith
between every pair in the group of mutually disjoint classes, making such statements
of disjointness more concise, easier to read, and less error prone. Another OWL 2
proper t y,
owl:disjointUnion
,
allows the specification of all possible disjoint
subclasses of a class. Using the tax example, the following states that a
Premises
is exclusively either a
BusinessPremises
or a
ResidentialPremises
and
cannot be both of them (at least from the perspective of Merean taxation):
Business Premises and Residential
Premises are mutually exclusive.
Premises is a kind of
Business Premises or
Residential Premises.
2
Class: Premises
DisjointUnion: BusinessPremises,
ResidentialPremises
Disjoint Classes and Disjoint Union are often called “syntactic sugar” as their
meanings can be constructed using multiple Disjoint With and Union statements.
They are just offered as a shorthand alternative rather than to provide new expres-
sivity to the language.
9.3.3 i
nDiviDuaLs
An “Individual” is the name given in OWL to instances or members of a class, and
statements about individuals are contained in the Abox. We can state that “The Isis
Tavern is a Pub.” in the following way:
The Isis Tavern is a Pub.
The Isis Tavern has name
“The Isis Tavern”.
The Isis Tavern and Frog and
Frigate are different things.
Individual:
Types: Pub
Facts: hasName value “The Isis
Tavern”^^xsd:string
DifferentFrom:
This says that the information resource controlled by Merea Maps with URI
http://id mereamaps.gov.me/topo/0012
is a member of the class Pub and
has the name (as a string value) “The Isis Tavern,” using the Manchester Syntax
keyword “Facts,” and that it is a different individual from the pub represented by the
The construct
owl:AllDifferent
states that in a list of individuals, all are
mutually distinct from each other and can be used as a shortcut instead of making
separate pairwise statements using
owl:differentFrom
. The Manchester Syntax
uses the keyword
DifferentIndividuals
to denote this:
DifferentIndividuals: AshFleetFarm, HomeFarm, IsisFarm
