diff --git a/spec/index.html b/spec/index.html index a4a1c2b..9433fc8 100644 --- a/spec/index.html +++ b/spec/index.html @@ -67,8 +67,8 @@ are comprised of a default graph and zero or more named graphs. -

RDF 1.2 introduces triple terms as another kind of RDF term - which can be used as the object of another triple. +

RDF 1.2 introduces the ability to use an RDF triple + as a triple term, in the object position of another triple. RDF 1.2 also introduces directional language-tagged strings, which contain a base direction element that allows the initial text direction to be specified for presentation by a user agent.

@@ -288,9 +288,8 @@

RDF Vocabularies and Namespace IRIs

Triple Terms and Reification

-

A triple term is an RDF term with the components of - an RDF triple, which can be used as the object - of another triple.

+

A triple term is an [=RDF triple=] used as an [=RDF term=] + in the [=object=] position of another triple.

A triple term is not necessarily asserted, allowing statements to be made about other statements that may not be @@ -417,12 +416,14 @@

Working with Multiple RDF Graphs

Equivalence, Entailment and Inconsistency

-

An RDF triple encodes a statement—a - simple logical expression, or claim about the world. +

An RDF triple encodes a proposition — a + simple logical expression, describing a relationship between two entities. + An [=asserted triple=] is a claim that the corresponding proposition is true. An RDF graph is the conjunction (logical AND) of - its triples. The precise details of this meaning of RDF triples and graphs are + all the claims made by its [=asserted triples=]. + The precise details of this meaning of [=RDF triples=] and [=RDF graphs=] are the subject of [[[RDF12-SEMANTICS]]] [[RDF12-SEMANTICS]], which yields the - following relationships between RDF graphs:

+ following relationships between RDF graphs:

Entailment
@@ -547,21 +548,45 @@

RDF Graphs

An RDF graph is a set of RDF triples.

-

An RDF triple is said to be asserted in an RDF graph if it is an element of the RDF graph.

+

An [=RDF triple=] is said to be asserted in an [=RDF graph=] if it is an element of the [=RDF graph=]. +

Triples

-

An RDF triple (usually called "triple") - is a 3-tuple (|s|, |p|, |o|) with the following characteristics:

+

An RDF triple + (often simply called "triple") + is a 3-tuple that is defined inductively as follows:

    -
  • |s| is an IRI or a blank node.
  • -
  • |p| is an IRI.
  • -
  • |o| is an IRI, a blank node, a literal, - or a triple term.
  • +
  • + If |s| is an [=IRI=] or a [=blank node=], + |p| is an [=IRI=], and + |o| is an [=IRI=], a [=blank node=], or a [=literal=], + then (|s|, |p|, |o|) is an [=RDF triple=]. +
  • + +
  • + If |s| is an [=IRI=] or a [=blank node=], + |p| is an [=IRI=], and + |o| is an [=RDF triple=], + then (|s|, |p|, |o|) is an [=RDF triple=]. +
+

The three components (|s|, |p|, |o|) of an [=RDF triple=] are respectively called the subject, predicate and object of the triple.

+ + +

The definition of triple is recursive. + That is, a triple can itself have an + object component which is another triple. + However, by this definition, cycles of triples cannot be created.

+
+ +
+

RDF Terms

+

IRIs, literals, blank nodes, and triple terms are collectively known as RDF terms.

@@ -575,8 +600,8 @@

Triples

http://example.org/.

The set of nodes of an RDF graph - is the set of subjects and objects of the triples in the graph. - It is possible for a predicate IRI to also occur as a node in + is the set of subjects and objects of the asserted triples of the graph. + It is possible for a [=predicate=] [=IRI=] to also occur as a [=node=] in the same graph.

@@ -851,49 +876,26 @@

Blank Nodes

Triple Terms

-

A triple term is a 3-tuple that is defined recursively as follows:

+

An [=RDF triple=] used as the [=object=] of another [=triple=] is called a triple term. + In a given [=RDF graph=], a [=triple=] can appear as a [=triple term=], an [=asserted triple=], or both. +

-
    -
  • - If |s| is an IRI or a blank node, - |p| is an IRI, and - |o| is an IRI, a blank node, or a literal, - then (|s|, |p|, |o|) is a triple term. -
  • +

    The set of [=RDF terms=] appearing in an [=RDF triple=] |t| is defined inductively as follows:

    -
  • - If |s| is an IRI or a blank node, - |p| is an IRI, and - |o| is a triple term, - then (|s|, |p|, |o|) is a triple term. -
  • +
      +
    • The [=subject=], [=predicate=] and [=object=] of |t| [=appear=] in |t|. +
    • If a [=triple term=] |t2| appears in |t|, then any [=RDF term=] [=appearing=] in |t2| also [=appears=] in |t|.
    -

    Given a triple (|s|, |p|, |o|), - |s| is called the subject of the triple, - |p| is called the predicate of the triple, and - |o| is called the object of the triple. - Similarly, given a triple term (|s|, |p|, |o|), - |s| is called the subject of the triple term, - |p| is called the predicate of the triple term, and - |o| is called the object of the triple term.

    - -

    While, syntactically, the notion of an RDF triple - and the notion of a triple term are the same, they represent - different concepts. RDF triples are the members of RDF graphs, - whereas triple terms can be used as components of RDF triples.

    - -

    The definition of triple term is recursive. - That is, a triple term can itself have an - object component which is another triple term. - However, by this definition, cycles of triple terms cannot be created.

    - -

    Every triple with a triple term as its object SHOULD +

    By extension, an [=RDF term=] is said to [=appear=] in an [=RDF graph=] if it appears in an [=asserted triple=] of that graph. An [=RDF triple=] is said to [=appear=] in an [=RDF graph=] if it is either an [=asserted triple=] of that graph or a [=triple term=] [=appearing=] in that graph.

    + +

    Every triple with a triple term as its [=object=] SHOULD use http://www.w3.org/1999/02/22-rdf-syntax-ns#reifies (rdf:reifies) as its predicate. Every triple whose object is not a triple term SHOULD NOT use http://www.w3.org/1999/02/22-rdf-syntax-ns#reifies (rdf:reifies) as its predicate.

    +