RDF Terminology and Concepts

5 January 2001
Graham Klyne
Graham Klyne
Brian McBride

This is currently a live working document, being a collection of suggestions from participants in the W3C RDF Interest Group.


Web Resource:
Anything that is identified by a URI [RRC2396].
RDF Resource:
[See RDF M&S section 5] Note that an RDF resource is not necessarily a web resource, though any web resource can be an RDF resource.
Consider: http://foo.com/#a and http://foo.com/#b may name distinct RDF resources, but if used to access web resources they both refer to the common web resource http://foo.com/.
RDF Statement, Statement:
[See RDFM&S section 5]
RDF Description:
[See RDFM&S] Construct containing representations of a number of RDF statements about a specific RDF resource, and possibly some additional statements.
Description [of]:
(As opposed to RDF Description) Language or data structure providing information about some entity or concept.
Reification (of a statement):
[See RDFM&S section 5] A resource that stands for the statement together with the four statements that describe the statement. (In my opinion, a reification of a statement is not unique: there may be more than one reification of any given statement.)
Reified statment:
[See RDFM&S section 5] A resource that stands for a statement. This resource has four properties describing the statement, and maybe others.
(There is some debate about whether or not a statement has a unique reification, or if all reifications of a statement are to be regarded as equivalent.)
A data structure (abstract or concrete) that captures some essential properties of some entity or concept.
Representing [x]:
Being a representation of [x] (see above)
An environment within which some statements are taken to be true.
A reference to a statement without necessarily making any assertion about its truth or falsity.
The expression of an RDF statement [or set of statements] in some context of discourse that is taken to be an assertion of the truth of the statement[s] in that context.
[See RDFM&S section 5].
This term is used in three distinct ways:
(a) The RDF Model, meaning the underlying structure and interpretation of RDF data
(b) An RDF Model, meaning a collection of RDF statements
(c) Logical Model, being a formal logicians term with quite specific meaning. (see http://www-rci.rutgers.edu/~cfs/305_html/Deduction/FormalSystemDefs.html).
(I've tried to stop using this term, since it has a quite specific meaning to logicians, that is not the same as what I would regard as its "natural" meaning.)
RDF Graph:
A set of RDF Statements.
Reification of an RDF Graph:
A (bag/collection?) containing the reifications of the statements in an RDF Graph
Reified Graph:
The (bag/collection?) in the reification of an RDF graph.




Insightful comments were provided by Pierre-Antoine Champin and Bill dehOra.