Update Linked Data definition based on discussions. This relates to issue #47.
--- a/spec/latest/json-ld-api/index.html Wed Aug 29 17:35:36 2012 -0700
+++ b/spec/latest/json-ld-api/index.html Wed Aug 29 18:37:34 2012 -0700
@@ -686,48 +686,43 @@
A <tref>JSON object</tref> used to reference a node having only the
<code>@id</code> key.</dd>
<dt><tdef>Linked Data</tdef></dt>
- <dd>A set of documents, each containing a representation of a
- <tref>linked data graph</tref>.</dd>
+ <dd>A set of documents, each containing a representation of a <tref>linked data graph</tref>.</dd>
<dt><tdef>linked data graph</tdef> or <tdef>dataset</tdef></dt>
- <dd>An unordered labeled directed graph, where <tref>node</tref>s are
- <tref>subject</tref>s or <tref>object</tref>s, and edges are
- properties.</dd>
+ <dd>An unordered labeled directed graph, where <tref>node</tref>s are <tref title="IRI">IRIs</tref> or <tref title="Blank Node">Blank Nodes</tref>, or other values.
+ A linked data graph may be named using a <tref>graph name</tref>.
+ A <tref>linked data graph</tref> is a generalized representation of a
+ <cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-rdf-graph">RDF graph</a></cite>
+ as defined in [[!RDF-CONCEPTS]].</dd>
<dt><tdef>node</tdef></dt>
- <dd>A piece of information that is represented in a
- <tref>linked data graph</tref>.</dd>
+ <dd>A piece of information that is represented in a <tref>linked data graph</tref>.</dd>
<dt><tdef>named graph</tdef></dt>
<dd>A <tref>linked data graph</tref> that has one or more
- <tref>IRI</tref> that are used to refer to it.</dd>
+ <tref>IRI</tref> that are used to refer to it.</dd>
<dt><tdef>graph name</tdef></dt>
- <dd>An <tref>IRI</tref> that is a reference to a
- <tref>named graph</tref>.</dd>
+ <dd>An <tref>IRI</tref> that is a reference to a <tref>named graph</tref>.</dd>
<dt><tdef>default graph</tdef></dt>
<dd>When executing an algorithm, the graph where data should be placed
- if a <tref>named graph</tref> is not specified.</dd>
+ if a <tref>named graph</tref> is not specified.</dd>
<dt><tdef>subject</tdef></dt>
- <dd>Any node in a <tref>linked data graph</tref> with at least one
- outgoing edge.</dd>
+ <dd>A <tref>node</tref> in a <tref>linked data graph</tref> with at least one outgoing edge, related to an <tref>object</tref> node through a <tref>property</tref>.</dd>
<dt><tdef><abbr title="Internationalized Resource Identifier">IRI</abbr></tdef></dt>
<dd>An Internationalized Resource Identifier as described in [[!RFC3987]].</dd>
<dt><tdef>object</tdef></dt>
- <dd>A node in a <tref>linked data graph</tref> with at least one
- incoming edge.</dd>
+ <dd>A <tref>node</tref> in a <tref>linked data graph</tref> with at least one incoming edge.</dd>
<dt><tdef>property</tdef></dt>
- <dd>An edge of the <tref>linked data graph</tref>.</dd>
+ <dd>The <tref>IRI</tref> label of an edge in a <tref>linked data graph</tref>.</dd>
<dt><tdef>literal</tdef></dt>
- <dd>An <tref>object</tref> with a label that is not an
- <tref>IRI</tref>.</dd>
+ <dd>An <tref>object</tref> expressed as a value such as a string, number or <tref>expanded value</tref>.</dd>
<dt><tdef>quad</tdef></dt>
<dd>A piece of information that contains four items; a
- <tref>subject</tref>, a <tref>property</tref>, a <tref>object</tref>,
- and a <tref>graph name</tref>.</dd>
+ <tref>subject</tref>, a <tref>property</tref>, a <tref>object</tref>,
+ and a <tref>graph name</tref>. <span class="issue">normalize use of <em>property</em> and <em>predicate</em>.</span></dd>
<dt><tdef>context</tdef></dt>
- <dd>A <tref>JSON object</tref> that contains rules for interpreting a
- JSON-LD document.</dd>
+ <dd>A <tref>JSON object</tref> that contains rules for interpreting a JSON-LD document.</dd>
<dt><tdef>keyword</tdef></dt>
<dd>A JSON key that is specific to JSON-LD, specified in the JSON-LD
- Syntax specification [[!JSON-LD]] in the section titled
- <a href="../json-ld-syntax/#syntax-tokens-and-keywords">Syntax Tokens and Keywords</a>.</dd>
+ Syntax specification [[!JSON-LD]] in the section titled
+ <a href="../json-ld-syntax/#syntax-tokens-and-keywords">Syntax Tokens and Keywords</a>.</dd>
</dl>
</section>
@@ -1507,7 +1502,7 @@
<section>
<h2>Value Compaction</h2>
<p>Some values, such as <tref title="IRI">IRIs</tref> and <tref title="typed literal">typed literals</tref>, may be expressed in an
- expanded form in JSON-LD. These values are required to be compacted at
+ expanded form (<tdef>expanded value</tdef>) in JSON-LD. These values are required to be compacted at
times when processing JSON-LD documents.
</p>
--- a/spec/latest/json-ld-framing/index.html Wed Aug 29 17:35:36 2012 -0700
+++ b/spec/latest/json-ld-framing/index.html Wed Aug 29 18:37:34 2012 -0700
@@ -362,12 +362,17 @@
</p>
<ol>
<li><tdef>Linked Data</tdef> is a set of documents, each containing a representation of a <tref>linked data graph</tref>.</li>
- <li>A <tdef>linked data graph</tdef> is an unordered labeled directed graph, where <tref title="node">nodes</tref> are <tref>subject</tref>s or <tref>object</tref>s, and edges are properties.
+ <li>A <tdef>linked data graph</tdef> is an unordered labeled directed graph, where <tdef>node</tdef>s are <tref title="IRI">IRIs</tref> or <tref title="Blank Node">Blank Nodes</tref>, or other values.
A linked data graph may be named using a <tdef>graph name</tdef>.
A <tref>linked data graph</tref> is a generalized representation of a
<cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-rdf-graph">RDF graph</a></cite>
as defined in [[!RDF-CONCEPTS]].</li>
- <li>A <tdef>node</tdef> may be an <tref>IRI</tref>, <tref>blank node</tref>, or <tref>literal</tref>.</li>
+ <li>A <tref>node</tref> having an outgoing edge MUST be an <tref>IRI</tref> or <tref>Blank Node</tref>.</li>
+ <li>A <tref>node</tref> having an incoming edge MUST be an <tref>IRI</tref>, <tref>Blank Node</tref>, or value such as a number or string.</li>
+ <li>A <tref>node</tref> MAY have both incoming and outgoing edges.</li>
+ <li>An edge MUST be labeled with an absolute IRI, within the JSON-LD syntax, this label is called a <tdef>property</tdef>.</li>
+ <li>Two nodes related by an edge form a <tdef>statement</tdef> where the nodes are referred to <tdef>subject</tdef> and <tdef>object</tdef> and the edge referred to as the <tdef>predicate</tdef>*.</li>
+ <li><tref title="IRI">IRIs</tref> used within a <tref>linked data graph</tref> SHOULD be dereferenceable to a <tref>Linked Data</tref> document describing the resource denoted by that <tref>IRI</tref>.</li>
<li>An <tdef><abbr title="Internationalized Resource Identifier">IRI</abbr></tdef> (an Internationalized Resource Identifier) is described in [[!RFC3987]])
and the use with JSON-LD conforms to the definition of
<cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-iri">IRI</a></cite> in [[!RDF-CONCEPTS]].</li>
@@ -378,19 +383,11 @@
a <tref>node</tref> See
<cite><a href="http://www.w3.org/TR/rdf11-concepts/#section-multigraph">Abstract Syntax for Working with Multiple Graphs</a></cite>
in [[!RDF-CONCEPTS]].</li>
- <li>A <tdef>subject</tdef> is any <tref>node</tref> in a <tref>linked data graph</tref> with at least one outgoing edge.</li>
- <li>An <tdef>object</tdef> is a <tref>node</tref> in a <tref>linked data graph</tref> with at least one incoming edge.</li>
- <li>An object MAY be a <tref>subject</tref> and <tref>object</tref> at the same time.</li>
- <li>A <tdef>property</tdef> is an edge of the <tref>linked data graph</tref>.
- Also known as a <tdef>predicate</tdef> in [[!RDF-CONCEPTS]].</li>
- <li>A <tref>property</tref> SHOULD be an <tref>IRI</tref>. To be converted
- to or from RDF, a <tref>property</tref> MUST be an <tref>IRI</tref></li>
<li>A <tdef>blank node</tdef> is a <tref>node</tref> which is neither an <tref>IRI</tref> nor a <tref>literal</tref>
but represents an unknown <tref>node</tref>, which may be either an <tref>IRI</tref> or a <tref>literal</tref>.
Within a document, a <tref>blank node</tref> may have an identifier used for intra-document reference
purposes only. See [[!RDF-CONCEPTS]] for a further description of
- <cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-blank-node">blank nodes</a></cite>.</li>
- <li>An <tref>IRI</tref> <tref>node</tref> in a <tref>linked data graph</tref> SHOULD be identify a <tref>Linked Data</tref> <em>resource</em> describing the <tref>subject</tref>, <tref>object</tref> or <tref>property</tref>.</li>
+ <cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-blank-node">blank nodes</a></cite>.</li>
<li>A <tdef>literal</tdef> is used to identify values such as numbers and dates.
A <tref>literal</tref> may be an <tref>object</tref> in a <tref>linked data graph</tref>.
See [[!RDF-CONCEPTS]] for a further definition of
@@ -405,20 +402,19 @@
<div class="issue" data-number="47">
<p>Richard Cyganiak suggests that the data model is at odds with [[RDF-CONCEPTS]] and should
be more closely aligned with it instead of creating new terminology.</p>
- <p>One proposal requiring further discussion would be to simplify the Linked Data definition
- to something like this:</p>
+ <p>Note that this definition is provisional, and may be reverted to something closer to the original depending on community feedback.</p>
<ol>
- <li>Linked Data is a set of documents, each containing a representation of a linked data graph.</li>
- <li>A linked data graph is an unordered labeled directed graph.</li>
- <li>A node having an outgoing edge MUST be an IRI or Blank Node.</li>
- <li>A node having an incoming edge MUST be an IRI, Blank Node or value such as a number or a string.</li>
- <li>A node MAY have both incoming and outgoing edges.</li>
- <li>An edge MUST be an absolute IRI.</li>
- <li>Two nodes related by an edge form a <em>statement</em> where the nodes are referred to <em>subject</em>
- and <em>object</em> and the edge referred to as the <em>predicate</em>.
- <strong>(At Risk, we may not need to talk about subjects, predicates or objects at all).</strong></li>
- <li>IRIs used within a linked data graph SHOULD be dereferenceable to a Linked Data document describing
- the resource denoted by that IRI.</li>
+ <li><tref>Linked Data</tref> is a set of documents, each containing a representation of a <tref>linked data graph</tref>.</li>
+ <li>A <tref>linked data graph</tref> is an unordered labeled directed graph, where nodes are <tref>subject</tref>s or <tref>object</tref>s, and edges are labeled using <tref title="property">properties</tref>.</li>
+ <li>A <tref>subject</tref> is any node in a <tref>linked data graph</tref> with at least one outgoing edge.</li>
+ <li>A <tref>subject</tref> SHOULD be labeled with an <tref><abbr title="Internationalized Resource Identifier">IRI</abbr></tref> (an Internationalized Resource Identifier as described in [[!RFC3987]]).</li>
+ <li>An <tref>object</tref> is a node in a <tref>linked data graph</tref> with at least one incoming edge.</li>
+ <li>An <tref>object</tref> MAY be labeled with an <tref>IRI</tref> or a label that is not an <tref>IRI</tref> such as plain text, internationalized text, or a strictly-typed data value.</li>
+ <li>A node MAY be a <tref>subject</tref> and an <tref>object</tref> at the same time.</li>
+ <li>A <tref>property</tref> is the label on an edge in a
+ <tref>linked data graph</tref>.</li>
+ <li>A <tref>property</tref> SHOULD be an <tref>IRI</tref>.</li>
+ <li>An <tref>IRI</tref> that is a label in a <tref>linked data graph</tref> SHOULD be dereferencable to a <tref>Linked Data</tref> document describing the labeled <tref>subject</tref>, <tref>property</tref> or <tref>object</tref>.</li>
</ol>
</div>
--- a/spec/latest/json-ld-syntax/index.html Wed Aug 29 17:35:36 2012 -0700
+++ b/spec/latest/json-ld-syntax/index.html Wed Aug 29 18:37:34 2012 -0700
@@ -516,37 +516,42 @@
</p>
<ol>
<li><tdef>Linked Data</tdef> is a set of documents, each containing a representation of a <tref>linked data graph</tref>.</li>
- <li>A <tdef>linked data graph</tdef> is an unordered labeled directed graph, where nodes are <tref>subject</tref>s or <tref>object</tref>s, and edges are labeled using <tref title="property">properties</tref>.</li>
- <li>A <tdef>subject</tdef> is any node in a <tref>linked data graph</tref> with at least one outgoing edge.</li>
- <li>A <tref>subject</tref> SHOULD be labeled with an <tdef><abbr title="Internationalized Resource Identifier">IRI</abbr></tdef> (an Internationalized Resource Identifier as described in [[!RFC3987]]).</li>
- <li>An <tdef>object</tdef> is a node in a <tref>linked data graph</tref> with at least one incoming edge.</li>
- <li>An <tref>object</tref> MAY be labeled with an <tref>IRI</tref> or a label that is not an <tref>IRI</tref> such as plain text, internationalized text, or a strictly-typed data value.</li>
- <li>A node MAY be a <tref>subject</tref> and an <tref>object</tref> at the same time.</li>
- <li>A <tdef>property</tdef> is the label on an edge in a
- <tref>linked data graph</tref>.</li>
- <li>A <tref>property</tref> SHOULD be an <tref>IRI</tref>.</li>
- <li>An <tref>IRI</tref> that is a label in a <tref>linked data graph</tref> SHOULD be dereferencable to a <tref>Linked Data</tref> document describing the labeled <tref>subject</tref>, <tref>property</tref> or <tref>object</tref>.</li>
+ <li>A <tdef>linked data graph</tdef> is an unordered labeled directed graph, where <tdef title="node">nodes</tdef> are <tref title="IRI">IRIs</tref> or <tref title="Blank Node">Blank Nodes</tref>, or other values.</li>
+ <li>A <tref>node</tref> having an outgoing edge MUST be an <tref>IRI</tref> or <tref>Blank Node</tref>.</li>
+ <li>A <tref>node</tref> having an incoming edge MUST be an <tref>IRI</tref>, <tref>Blank Node</tref>, or value such as a number or string.</li>
+ <li>A <tref>node</tref> MAY have both incoming and outgoing edges.</li>
+ <li>An edge MUST be labeled with an <tref>absolute IRI</tref>, within the JSON-LD syntax, this label is called a <tdef>property</tdef>.</li>
+ <li>Two nodes related by an edge form a <tdef>statement</tdef> where the nodes are referred to <tdef>subject</tdef> and <tdef>object</tdef> and the edge referred to as the <tdef>predicate</tdef>*.</li>
+ <li><tref title="IRI">IRIs</tref> used within a <tref>linked data graph</tref> SHOULD be dereferenceable to a <tref>Linked Data</tref> document describing the resource denoted by that <tref>IRI</tref>.</li>
</ol>
+<div class="note">
+ <p>A <tref>Linked Data</tref> document does not necessarily need to be expressed in JSON-LD. The notion of
+ <tref>Linked Data</tref> is a concept independent of any given serialization format. In particular, any document based on
+ an RDF serialization format is a <tref>Linked Data</tref> document.</p>
+
+ <p>This definition of <tref>Linked Data</tref> is entirely consistent with that in [[RDF-CONCEPTS]], although
+ <tref>Linked Data</tref> may not be a valid RDF document, any RDF document is an expression of <tref>Linked Data</tref>.</p>
+</div>
+
<p class="issue">An illustration of a linked data graph would probably help here.</p>
<div class="issue" data-number="47">
<p>Richard Cyganiak suggests that the data model is at odds with [[RDF-CONCEPTS]] and should
be more closely aligned with it instead of creating new terminology.</p>
- <p>One proposal requiring further discussion would be to simplify the Linked Data definition
- to something like this:</p>
+ <p>Note that this definition is provisional, and may be reverted to something closer to the original depending on community feedback.</p>
<ol>
- <li>Linked Data is a set of documents, each containing a representation of a linked data graph.</li>
- <li>A linked data graph is an unordered labeled directed graph.</li>
- <li>A node having an outgoing edge MUST be an IRI or Blank Node.</li>
- <li>A node having an incoming edge MUST be an IRI, Blank Node or value such as a number or a string.</li>
- <li>A node MAY have both incoming and outgoing edges.</li>
- <li>An edge MUST be an absolute IRI.</li>
- <li>Two nodes related by an edge form a <em>statement</em> where the nodes are referred to <em>subject</em>
- and <em>object</em> and the edge referred to as the <em>predicate</em>.
- <strong>(At Risk, we may not need to talk about subjects, predicates or objects at all).</strong></li>
- <li>IRIs used within a linked data graph SHOULD be dereferenceable to a Linked Data document describing
- the resource denoted by that IRI.</li>
+ <li><tref>Linked Data</tref> is a set of documents, each containing a representation of a <tref>linked data graph</tref>.</li>
+ <li>A <tref>linked data graph</tref> is an unordered labeled directed graph, where nodes are <tref>subject</tref>s or <tref>object</tref>s, and edges are labeled using <tref title="property">properties</tref>.</li>
+ <li>A <tref>subject</tref> is any node in a <tref>linked data graph</tref> with at least one outgoing edge.</li>
+ <li>A <tref>subject</tref> SHOULD be labeled with an <tref><abbr title="Internationalized Resource Identifier">IRI</abbr></tref> (an Internationalized Resource Identifier as described in [[!RFC3987]]).</li>
+ <li>An <tref>object</tref> is a node in a <tref>linked data graph</tref> with at least one incoming edge.</li>
+ <li>An <tref>object</tref> MAY be labeled with an <tref>IRI</tref> or a label that is not an <tref>IRI</tref> such as plain text, internationalized text, or a strictly-typed data value.</li>
+ <li>A node MAY be a <tref>subject</tref> and an <tref>object</tref> at the same time.</li>
+ <li>A <tref>property</tref> is the label on an edge in a
+ <tref>linked data graph</tref>.</li>
+ <li>A <tref>property</tref> SHOULD be an <tref>IRI</tref>.</li>
+ <li>An <tref>IRI</tref> that is a label in a <tref>linked data graph</tref> SHOULD be dereferencable to a <tref>Linked Data</tref> document describing the labeled <tref>subject</tref>, <tref>property</tref> or <tref>object</tref>.</li>
</ol>
</div>
@@ -881,12 +886,17 @@
<section>
<h2>IRIs</h2>
-<p><tref>IRI</tref>s are fundamental to <tref>Linked Data</tref>
-as that is how most <tref>nodes</tref>s and all
+<p><tref title="IRI">IRIs</tref> are fundamental to <tref>Linked Data</tref>
+as that is how most <tref title="node">nodes</tref>s and all
<tref title="property">properties</tref> are
identified. <tref>IRI</tref>s can be expressed in a variety of different ways
in JSON-LD.</p>
+<p>An <tdef><abbr title="Internationalized Resource Identifier">IRI</abbr></tdef>
+ (an Internationalized Resource Identifier) is described in [[!RFC3987]])
+ and the use with JSON-LD conforms to the definition of
+ <cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-iri">IRI</a></cite> in [[!RDF-CONCEPTS]].</p>
+
<ol>
<li>Except within a <tref>context</tref> definition, <tref>term</tref>s in the key position in
a <tref>JSON object</tref> that have a mapping or a vocabulary base <tref>IRI</tref> in the
@@ -2375,7 +2385,7 @@
<p>At times, it becomes necessary to be able to express information without
being able to specify the node. Typically, this type of node is called
-an <tdef>unlabeled node</tdef> or a blank node (see [[!RDF-CONCEPTS]] <cite><a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">Section 3.4: Blank Nodes</a></cite>).
+an <tdef>unlabeled node</tdef> or a <tdef>blank node</tdef> (see [[!RDF-CONCEPTS]] <cite><a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">Section 3.4: Blank Nodes</a></cite>).
In JSON-LD, <tref>unlabeled node</tref> identifiers are
automatically created if a node is not specified using the
<code>@id</code> <tref>keyword</tref>. However, authors may provide identifiers for