Change - Web Ontology Language

Created on March 11, 2013, 4:07 p.m. by Hevok & updated on March 11, 2013, 4:07 p.m. by Hevok

The Semantic Web Ontology Language (OWL) is the Semantic Web Version of the Description Logic SHROIQ(D) which has a special Language and Syntax, but its Semantics in the end comes to the Description Logics. ¶
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The Web Ontology Language depends or corresponds to a Description Logics. The two different version of OWL, OWL 1 and OWL2 depend on different Description Logics. OWL 1 on SHOIN(D) and OWL 2 on SHROIQ(D) ¶
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With OWL one defines Ontologies. An OWL Ontology consists out of Classes, Properties and Individuals. Individuals are Instances of Classes. A Property corresponds to a Role in Description Logics. ¶
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In general in OWL as well as in Description Logics, the Open World Assumption holds, which means that the absence of Information must not be evaluated as negative Information. ¶
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Also for OWL the Unique Name Assumption does not hold. This means that differences between Entities and Classes must be expressed explicitly. For example Person A may denote the same Person as Person B. ¶
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So if two persons or two Instances really are different, then one has to express this in an explicit way. ¶
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OWL (SHOIN(D)) - W3C Recommendation since 2004 ¶
OWL 2 (SHROIQ(D)) - W3C Recommendation since 2009 ¶
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OWL Ontology consists of ¶
- Classes ¶
- Properties ¶
- Individuals (Instances of Classes) ¶
Open World Assumption ¶
- "Absence of Information must not be valued as negative Information." ¶
+ E.g. sitsNextTo(PersonA, PersonB) ¶
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PersonA may also sit next to anohter person... ¶
* No Unique Name Assumption ¶
- "Difference must be expressed explicitly" ¶
+ E.g. PersonA possibly denotes the same Individual as PersonB