The unique name assumption is a simplifying assumption made in some
ontology
Ontology is the philosophical study of existence, being. It is traditionally understood as the subdiscipline of metaphysics focused on the most general features of reality. As one of the most fundamental concepts, being encompasses all of realit ...
languages and
description logic
Description logics (DL) are a family of formal knowledge representation languages. Many DLs are more expressive than propositional logic but less expressive than first-order logic. In contrast to the latter, the core reasoning problems for DLs are ...
s. In logics with the unique name assumption, different names always refer to different entities in the world.
It was included in
Ray Reiter
Raymond Reiter (; June 12, 1939 – September 16, 2002) was a Canadian computer scientist and logician. He was one of the founders of the field of non-monotonic reasoning with his work on default logic, model-based diagnosis, closed-world ...
's discussion of the
closed-world assumption often tacitly included in Database Management Systems (e.g. SQL) in his 1984 article "Towards a logical reconstruction of relational database theory" (in M. L. Brodie, J. Mylopoulos, J. W. Schmidt (editors), Data Modelling in Artificial Intelligence, Database and Programming Languages, Springer, 1984, pages 191–233).
The standard ontology language
OWL
Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...
does not make this assumption, but provides explicit constructs to express whether two names denote the same or distinct entities.
OWL Web Ontology Language Reference
/ref>
* owl:sameAs
In data science, sameAs or exactMatch is a method of indicating that the subject of, or entity represented by, two resources is considered to be one and the same thing. It is a key part of the Semantic Web.
Uses
The concept of sameAs exists ...
is the OWL property that asserts that two given names or identifiers (e.g., URIs) refer to the same individual or entity.
* owl:differentFrom is the OWL property that asserts that two given names or identifiers (e.g., URIs) refer to different individuals or entities.
See also
* Closed-world assumption
* Coreference
In linguistics, coreference, sometimes written co-reference, occurs when two or more expressions refer to the same person or thing; they have the same referent. For example, in ''Bill said Alice would arrive soon, and she did'', the words ''Alice'' ...
References
Knowledge representation
Ontology (information science)
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