Entities

Entities in the SNOMED CT Logic Profile are limited to the following entities as defined in the OWL 2 Specification section 5 Entities, Literals and Anonymous Individuals:

• Class

• ObjectProperty

• DataProperty

• Datatype

• Literal

• AnnotationProperty

Predefined classes and properties in OWL 2 are supported. SNOMED CT content will not have direct reference to them because they are implicitly presented in every OWL 2 Ontology.

The SNOMED CT Logic Profile supports the following datatypes:

• rdf:PlainLiteral

• rdf:XMLLiteral

• rdfs:Literal

• owl:real

• owl:rational

• xsd:decimal

• xsd:integer

• xsd:nonNegativeInteger

• xsd:string

• xsd:normalizedString

• xsd:token

• xsd:Name

• xsd:NCName

• xsd:NMTOKEN

• xsd:hexBinary

• xsd:base64Binary

• xsd:anyURI

• xsd:dateTime

• xsd:dateTimeStamp

The set of supported datatypes has been designed such that the intersection of the value spaces of any set of these datatypes is either empty or infinite, which is necessary to obtain the desired computational properties (refer to Pushing the EL Envelope). Consequently, the following datatypes must not be used in SNOMED CT:

• xsd:double,

• xsd:float,

• xsd:nonPositiveInteger,

• xsd:positiveInteger,

• xsd:negativeInteger,

• xsd:long,

• xsd:int,

• xsd:short,

• xsd:byte,

• xsd:unsignedLong,

• xsd:unsignedInt,

• xsd:unsignedShort,

• xsd:unsignedByte,

• xsd:language,

• and xsd:boolean.

The following entities, literals, and individuals are not supported

• DataRange

• Individual

• NamedIndividual

• AnonymousIndividual

Property Expressions

Inverse properties are not supported in the SNOMED Logic Profile, so object property expressions are restricted to named properties. Data property expressions are defined in the same way as in the OWL 2 structural specification.

Class Expressions

In order to allow for efficient reasoning, the SNOMED CT Logic Profile restricts the set of supported class expressions to ObjectIntersectionOf, ObjectSomeValuesFrom, and DataHasValue.

Data Ranges

A data range expression is restricted in the SNOMED CT Logic Profile to single data values, ranges and enumerations are not permitted.

Axioms

The class axioms of the SNOMED CT Logic Profile are the same as in the OWL 2 structural specification, with the exception that DisjointUnion is disallowed. Different class axioms are defined in the same way as in the OWL 2 structural specification, with the difference that they use the new definition of ClassExpression.

The SNOMED CT Logic Profile supports the following object property axioms, which are defined in the same way as in the OWL 2 structural specification, with the difference that they use the new definition of ObjectPropertyExpression.

The SNOMED CT Logic Profile does not support ObjectPropertyDomain and ObjectPropertyRange as they are supported via the SNOMED CT Machine Readable Concept Model.

The SNOMED CT Logic Profile supports the following axioms about data properties:

The SNOMED CT Logic Profile does not support the following axioms about data properties:

• DisjointDataProperties

• DataPropertyDomain and DataPropertyRange which are supported via the SNOMED CT Machine Readable Concept Model

The assertions in the SNOMED CT Logic Profile, as well as all other axioms, are the same as in the OWL 2 structural specification, with the difference that class object property expressions are restricted as defined in the previous sections.

Global Restrictions

The SNOMED CT Logic Profile does not apply the additional global restriction in section 2.2.6 Global Restrictions the OWL 2 EL profile. The condition this section applies is only relevant to  ObjectPropertyRange which the SNOMED CT Logic Profile does not support.