Empty graphs note
authorGavin Carothers <gavin@carothers.name>
Wed, 04 Sep 2013 09:53:50 -0700
changeset 1070 c74d550c39de
parent 1069 5a3d1835c438
child 1071 1f4f943af77b
Empty graphs note
drafts/n-quads/Overview.html
nquads/index.html
--- a/drafts/n-quads/Overview.html	Tue Sep 03 19:56:29 2013 -0700
+++ b/drafts/n-quads/Overview.html	Wed Sep 04 09:53:50 2013 -0700
@@ -3,9 +3,76 @@
 <head>
     <title>N-Quads</title>
     <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
-  
-  
-    
+  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js" class="remove"></script>
+  <script src="https://raw.github.com/darobin/respec/develop/builds/respec-w3c-common-3.1.62.js" async="" class="remove"></script>
+    <script class="remove">
+      var respecConfig = {
+          // specification status (e.g. WD, LCWD, NOTE, etc.). If in doubt use ED.
+          specStatus:           "LC",
+          
+          // the specification's short name, as in http://www.w3.org/TR/short-name/
+          shortName:            "n-quads",
+
+          // if your specification has a subtitle that goes below the main
+          // formal title, define it here
+          subtitle   :  "A line-based syntax for an RDF datasets",
+
+          "localBiblio" : {
+               "EBNF-NOTATION" : "Tim Bray; Jean Paoli; C. M. Sperberg-McQueen; Eve Maler; François Yergeau. <a href=\"http://www.w3.org/TR/REC-xml/#sec-notation\"><cite>EBNF Notation</cite></a> 26 November 2008. W3C Recommendation. URL: <a href=\"http://www.w3.org/TR/REC-xml/#sec-notation\">http://www.w3.org/TR/REC-xml/#sec-notation</a> "
+          },
+
+          // if you wish the publication date to be other than today, set this
+          publishDate:  "2013-09-04",
+
+          // if the specification's copyright date is a range of years, specify
+          // the start date here:
+          copyrightStart: "2012",
+
+          // if there is a previously published draft, uncomment this and set its YYYY-MM-DD date
+          // and its maturity status
+          previousPublishDate:  "2013-04-09",
+          previousMaturity:  "NOTE",
+
+          // if there a publicly available Editor's Draft, this is the link
+          edDraftURI:           "https://dvcs.w3.org/hg/rdf/raw-file/default/nquads/index.html",
+
+          // if this is a LCWD, uncomment and set the end of its review period
+          lcEnd: "2013-10-14",
+
+          // if you want to have extra CSS, append them to this list
+          // it is recommended that the respec.css stylesheet be kept
+          extraCSS:             ["http://dev.w3.org/2009/dap/ReSpec.js/css/respec.css"],
+
+          // editors, add as many as you like
+          // only "name" is required
+          editors:  [
+              { name: "Gavin Carothers", // url: "http://gavin.carothers.name/",
+    company: "Lex Machina, Inc", companyURL: "https://lexmachina.com/" },
+          ],
+
+          // authors, add as many as you like. 
+          // This is optional, uncomment if you have authors as well as editors.
+          // only "name" is required. Same format as editors.
+
+          // name of the WG
+          wg:           "RDF Working Group",
+          
+          // URI of the public WG page
+          wgURI:        "http://www.w3.org/2011/rdf-wg/",
+          
+          // name (with the @w3c.org) of the public mailing to which comments are due
+          wgPublicList: "public-rdf-comments",
+          
+          // URI of the patent status for this WG, for Rec-track documents
+          // !!!! IMPORTANT !!!!
+          // This is important for Rec-track documents, do not copy a patent URI from a random
+          // document unless you know what you're doing. If in doubt ask your friendly neighbourhood
+          // Team Contact.
+          wgPatentURI:  "http://www.w3.org/2004/01/pp-impl/46168/status",
+
+          // doRDFa: true,
+      };
+    </script>
       <style type="text/css">
     /* Style Turtle script blocks to be visable */
     pre.example script {
@@ -159,8 +226,47 @@
 aside.example div.example div.example-title {
     color: #999;
 }
-</style><link rel="stylesheet" href="https://www.w3.org/StyleSheets/TR/W3C-WD"></head>
-  <body class="h-entry" role="document" id="respecDocument"><div class="head" role="contentinfo" id="respecHeader">
+</style><style>/* --- ISSUES/NOTES --- */
+div.issue-title, div.note-title {
+    padding-right:  1em;
+    min-width: 7.5em;
+    color: #b9ab2d;
+}
+div.issue-title { color: #e05252; }
+div.note-title { color: #2b2; }
+div.issue-title span, div.note-title span {
+    text-transform: uppercase;
+}
+div.note, div.issue {
+    margin-top: 1em;
+    margin-bottom: 1em;
+}
+.note > p:first-child, .issue > p:first-child { margin-top: 0 }
+.issue, .note {
+    padding: .5em;
+    border-left-width: .5em;
+    border-left-style: solid;
+}
+div.issue, div.note {
+    padding: 1em 1.2em 0.5em;
+    margin: 1em 0;
+    position: relative;
+    clear: both;
+}
+span.note, span.issue { padding: .1em .5em .15em; }
+
+.issue {
+    border-color: #e05252;
+    background: #fbe9e9;
+}
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+    border-color: #52e052;
+    background: #e9fbe9;
+}
+
+
+</style><link rel="stylesheet" href="https://www.w3.org/StyleSheets/TR/W3C-WD"><script type="text/javascript" src="http://specref.jit.su/bibrefs?callback=setBerjonBiblio&amp;refs=RFC2119,UNICODE,EBNF-NOTATION,UTF-8,RFC3023,RFC3987,RFC3986,n-triples,turtle,UNICODE-SECURITY" class="remove"></script></head>
+  <body class="h-entry"><div class="head">
   <p>
     
       <a href="http://www.w3.org/"><img width="72" height="48" src="https://www.w3.org/Icons/w3c_home" alt="W3C"></a>
@@ -170,7 +276,7 @@
   
     <h2 property="bibo:subtitle" id="subtitle">A line-based syntax for an RDF datasets</h2>
   
-  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-09-04T07:00:00.000Z" id="w3c-last-call-working-draft-04-september-2013"><abbr title="World Wide Web Consortium">W3C</abbr> Last Call Working Draft <time class="dt-published" datetime="2013-09-04">04 September 2013</time></h2>
+  <h2 property="dcterms:issued" datatype="xsd:dateTime" content="2013-09-04T07:00:00.000Z"><abbr title="World Wide Web Consortium">W3C</abbr> Last Call Working Draft <time class="dt-published" datetime="2013-09-04">04 September 2013</time></h2>
   <dl>
     
       <dt>This version:</dt>
@@ -218,9 +324,9 @@
   
   <hr>
 </div>
-    <section id="abstract" class="introductory" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" resource="#abstract" rel="bibo:chapter"><h2 aria-level="1" role="heading" id="h2_abstract">Abstract</h2><p>
+    <section id="abstract" class="introductory"><h2>Abstract</h2><p>
     N-Quads is a line-based, plain text format for encoding an RDF dataset.
-</p></section><section id="sotd" class="introductory" typeof="bibo:Chapter" resource="#sotd" rel="bibo:chapter"><h2 aria-level="1" role="heading" id="h2_sotd">Status of This Document</h2>
+</p></section><section id="sotd" class="introductory"><h2>Status of This Document</h2>
   
     
       
@@ -288,12 +394,12 @@
       
     
   
-</section><section id="toc"><h2 class="introductory" aria-level="1" role="heading" id="h2_toc">Table of Contents</h2><ul class="toc" role="directory" id="respecContents"><li class="tocline"><a href="#sec-intro" class="tocxref"><span class="secno">1. </span>Introduction</a></li><li class="tocline"><a href="#n-quads-language" class="tocxref"><span class="secno">2. </span>N-Quads Language</a><ul class="toc"><li class="tocline"><a href="#simple-triples" class="tocxref"><span class="secno">2.1 </span>Simple Statements</a></li><li class="tocline"><a href="#sec-iri" class="tocxref"><span class="secno">2.2 </span>IRIs</a></li><li class="tocline"><a href="#sec-literals" class="tocxref"><span class="secno">2.3 </span>RDF Literals</a></li><li class="tocline"><a href="#BNodes" class="tocxref"><span class="secno">2.4 </span>RDF Blank Nodes</a></li></ul></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">3. </span>Conformance</a><ul class="toc"><li class="tocline"><a href="#sec-mediatype" class="tocxref"><span class="secno">3.1 </span>Media Type and Content Encoding</a></li></ul></li><li class="tocline"><a href="#sec-grammar" class="tocxref"><span class="secno">4. </span>Grammar</a></li><li class="tocline"><a href="#sec-parsing" class="tocxref"><span class="secno">5. </span>Parsing</a><ul class="toc"><li class="tocline"><a href="#sec-parsing-terms" class="tocxref"><span class="secno">5.1 </span>RDF Term Constructors</a></li><li class="tocline"><a href="#rdf-dataset-construction" class="tocxref"><span class="secno">5.2 </span>RDF Dataset Construction</a></li></ul></li><li class="tocline"><a href="#section-ack" class="tocxref"><span class="secno">6. </span>Acknowledgements</a></li><li class="tocline"><a href="#sec-changes" class="tocxref"><span class="secno">A. </span>Changes to this document</a></li><li class="tocline"><a href="#sec-mediaReg" class="tocxref"><span class="secno">B. </span>N-Quads Internet Media Type, File Extension and Macintosh File Type </a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></section>
+</section>
 
       
 
-      <section id="sec-intro" typeof="bibo:Chapter" resource="#sec-intro" rel="bibo:chapter">
-        <!--OddPage--><h2 aria-level="1" role="heading" id="h2_sec-intro"><span class="secno">1. </span>Introduction</h2>
+      <section id="sec-intro">
+        <h2>Introduction</h2>
         <p>This document defines an easy to parse line-based language named N-Quads.</p>
     <p>N-quads statments are a sequence of RDF terms representing the subject, predicate, object and graph label of an RDF Triple and the graph it is part of in a dataset. These may be separated by white space (spaces <code>#x20</code> or tabs <code>#x9</code>). This sequence is terminated by a '<code>.</code>' and a new line (optional at the end of a document).
     </p>
@@ -306,24 +412,24 @@
 
       </section>
 
-      <section id="n-quads-language">
-        <!--OddPage--><h2 aria-level="1" role="heading" id="h2_n-quads-language"><span class="secno">2. </span>N-Quads Language</h2>
-        <section id="simple-triples" typeof="bibo:Chapter" resource="#simple-triples" rel="bibo:chapter">
-          <h3 aria-level="2" role="heading" id="h3_simple-triples"><span class="secno">2.1 </span>Simple Statements</h3>
+      <section>
+        <h2>N-Quads Language</h2>
+        <section id="simple-triples">
+          <h3>Simple Statements</h3>
           <p>The simplest statement is a sequence of (subject, predicate, object) terms forming an RDF triple and an optional blank node label or IRI labeling what graph in a dataset the triple belongs to, all are separated by whitespace and terminated by '<code>.</code>' after each statement.</p>
           <div class="example"><div class="example-title"><span>Example 2</span></div><pre class="example"><script type="application/n-quads"><http://example.org/#spiderman> <http://www.perceive.net/schemas/relationship/enemyOf> <http://example.org/#green-goblin> <http://example.org/graphs/spiderman> .</script></pre></div>
           <p>The graph label IRI can be omitted, in which case the triples are considered part of the default graph of the RDF dataset.</p><p>
         </p></section>
-              <section id="sec-iri" typeof="bibo:Chapter" resource="#sec-iri" rel="bibo:chapter">
-        <h3 aria-level="2" role="heading" id="h3_sec-iri"><span class="secno">2.2 </span>IRIs</h3>
+              <section id="sec-iri">
+        <h3>IRIs</h3>
 
         <p>
             <a href="http://www.w3.org/TR/rdf11-concepts/#dfn-iri">IRIs</a> may be written only as absolute IRIs. 
             IRIs are enclosed in '&lt;' and '&gt;' and may contain numeric escape sequences (described below). For example <code>&lt;http://example.org/#green-goblin&gt;</code>.
         </p>
       </section>
-        <section id="sec-literals" typeof="bibo:Chapter" resource="#sec-literals" rel="bibo:chapter">
-              <h3 aria-level="2" role="heading" id="h3_sec-literals"><span class="secno">2.3 </span>RDF Literals</h3>
+        <section id="sec-literals">
+              <h3>RDF Literals</h3>
 
         <p><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-literal">Literals</a> are used to identify values such as strings, numbers, dates.</p>
 
@@ -336,8 +442,8 @@
           If there is no language tag, there may be a <a href="http://www.w3.org/TR/rdf11-concepts/#dfn-datatype-iri">datatype IRI</a>, preceeded by '<code>^^</code>' (<span class="codepoint">U+005E</span> <span class="codepoint">U+005E</span>). If there is no datatype IRI and no language tag, the datatype is <code>xsd:string</code>.
         </p>
         </section>
-      <section id="BNodes" typeof="bibo:Chapter" resource="#BNodes" rel="bibo:chapter">
-        <h3 aria-level="2" role="heading" id="h3_BNodes"><span class="secno">2.4 </span>RDF Blank Nodes</h3>
+      <section id="BNodes">
+        <h3>RDF Blank Nodes</h3>
         <p>
           <a href="http://www.w3.org/TR/rdf11-concepts/#dfn-blank-node">RDF blank nodes</a> in N-Quads are expressed as <code>_:</code> followed by a blank node label which is a series of name characters.
           The characters in the label are built upon <a href="#grammar-production-PN_CHARS_BASE">PN_CHARS_BASE</a>, liberalized as follows:
@@ -357,7 +463,7 @@
 
     </section>
 
-      <section id="conformance" typeof="bibo:Chapter" resource="#conformance" rel="bibo:chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_conformance"><span class="secno">3. </span>Conformance</h2>
+      <section id="conformance"><h2>Conformance</h2>
 <p>
   As well as sections marked as non-normative, all authoring guidelines, diagrams, examples,
   and notes in this specification are non-normative. Everything else in this specification is
@@ -373,14 +479,16 @@
                 <li>N-Quad documents
                 </li><li>N-Quad parsers
               </li></ul>
-      <p>A conforming <strong>N-Quad document</strong> is a Unicode string that conforms to the grammar and additional constraints defined in <a href="#sec-grammar" class="sectionRef sec-ref">section 4. Grammar</a>, starting with the <a href="#grammar-production-nquadsDoc"><code>nquadsDoc</code> production</a>. A N-Quad document serializes an RDF dataset.</p>
+      <p>A conforming <strong>N-Quad document</strong> is a Unicode string that conforms to the grammar and additional constraints defined in <a href="#sec-grammar" class="sectionRef"></a>, starting with the <a href="#grammar-production-nquadsDoc"><code>nquadsDoc</code> production</a>. A N-Quad document serializes an RDF dataset.</p>
 
-      <p>A conforming <strong>N-Quad parser</strong> is a system capable of reading N-Quad documents on behalf of an application. It makes the serialized RDF graph, as defined in <a href="#sec-parsing" class="sectionRef sec-ref">section 5. Parsing</a>, available to the application, usually through some form of API.</p>
+      <div class="note"><div class="note-title"><span>Note</span></div><p class="">N-Quad documents do not provide a way of serializing empty graphs that may be part of an RDF dataset.</p></div>
+
+      <p>A conforming <strong>N-Quad parser</strong> is a system capable of reading N-Quad documents on behalf of an application. It makes the serialized RDF graph, as defined in <a href="#sec-parsing" class="sectionRef"></a>, available to the application, usually through some form of API.</p>
 
       <p>The IRI that identifies the N-Quad language is: <code>http://www.w3.org/ns/formats/N-Quads</code></p>          
 
-        <section id="sec-mediatype" typeof="bibo:Chapter" resource="#sec-mediatype" rel="bibo:chapter">
-      <h3 aria-level="2" role="heading" id="h3_sec-mediatype"><span class="secno">3.1 </span>Media Type and Content Encoding</h3>
+        <section id="sec-mediatype">
+      <h2>Media Type and Content Encoding</h2>
           
       <p>The media type of N-Quads is <code>application/n-quads</code>.
       The content encoding of N-Quads is always UTF-8. 
@@ -390,8 +498,8 @@
         </section>
         </section>
 
-        <section id="sec-grammar" typeof="bibo:Chapter" resource="#sec-grammar" rel="bibo:chapter">
-          <!--OddPage--><h2 aria-level="1" role="heading" id="h2_sec-grammar"><span class="secno">4. </span>Grammar</h2>
+        <section id="sec-grammar">
+          <h3>Grammar</h3>
           <p>A N-Quads document is a Unicode[<cite><a class="bibref" href="#bib-UNICODE">UNICODE</a></cite>] character string encoded in UTF-8.
           Unicode codepoints only in the range U+0 to U+10FFFF inclusive are allowed.</p>
           <p>White space (tab <code>U+0009</code> or space <code>U+0020</code>) is used to separate two terminals which would otherwise be (mis-)recognized as one terminal. White space is significant in the production <a href="#grammar-production-STRING_LITERAL_QUOTE">STRING_LITERAL_QUOTE</a>.</p>
@@ -444,7 +552,7 @@
     <td>::=</td>
     <td><a href="#grammar-production-STRING_LITERAL_QUOTE">STRING_LITERAL_QUOTE</a> ('<code class="grammar-literal">^^</code>' <a href="#grammar-production-IRIREF">IRIREF</a> <code>| </code> '<code class="grammar-literal">@</code>' <a href="#grammar-production-LANGTAG">LANGTAG</a>)?</td>
 </tr>
-<tr><td colspan="4"><h2 id="terminals">Productions for terminals</h2></td></tr>
+<tr><td colspan="4"><h4 id="terminals">Productions for terminals</h4></td></tr>
             <tr id="grammar-production-LANGTAG" data-grammar-original="[144s] LANGTAG          ::= &quot;@&quot; [a-zA-Z]+ ( &quot;-&quot; [a-zA-Z0-9]+ )*" data-grammar-expression="(',', [(&quot;'&quot;, '@'), ('+', ('[', 'a-zA-Z')), ('*', (',', [(&quot;'&quot;, '-'), ('+', ('[', 'a-zA-Z0-9'))]))])" class="grammar-token">
     <td>[144s]</td>
     <td><code>LANGTAG</code></td>
@@ -514,16 +622,16 @@
 </tbody></table>
 </div>
         </section>
-        <section id="sec-parsing" typeof="bibo:Chapter" resource="#sec-parsing" rel="bibo:chapter">
-          <!--OddPage--><h2 aria-level="1" role="heading" id="h2_sec-parsing"><span class="secno">5. </span>Parsing</h2>
+        <section id="sec-parsing">
+          <h3>Parsing</h3>
           <p>Parsing N-Quads requires a state of one item:</p>
           <ul>
             <li id="bnodeLabels">Map[<a class="type string">string</a> -&gt; <a href="http://www.w3.org/TR/rdf11-concepts/#dfn-blank-node">blank node</a>] <code class="dfn">bnodeLabels</code> — A mapping from string to blank node.</li>
           </ul>
 
-          <section id="sec-parsing-terms" typeof="bibo:Chapter" resource="#sec-parsing-terms" rel="bibo:chapter">
-          <h3 aria-level="2" role="heading" id="h3_sec-parsing-terms"><span class="secno">5.1 </span>RDF Term Constructors</h3>
-              <p>This table maps productions and lexical tokens to <code>RDF terms</code> or components of <code>RDF terms</code> listed in <a href="#sec-parsing" class="sectionRef sec-ref">section 5. Parsing</a>:</p>
+          <section id="sec-parsing-terms">
+          <h3>RDF Term Constructors</h3>
+              <p>This table maps productions and lexical tokens to <code>RDF terms</code> or components of <code>RDF terms</code> listed in <a href="#sec-parsing" class="sectionRef"></a>:</p>
               <table class="simple">
                 <thead>
                   <tr><th>production</th><th>type</th><th>procedure</th></tr>
@@ -537,23 +645,23 @@
                 </tbody>
               </table>
           </section>
-          <section id="rdf-dataset-construction">
-            <h3 aria-level="2" role="heading" id="h3_rdf-dataset-construction"><span class="secno">5.2 </span>RDF Dataset Construction</h3>
+          <section>
+            <h3>RDF Dataset Construction</h3>
             <p>A N-Quad document defines an RDF dataset composed of RDF graphs composed of a set of RDF triples. The  <code><a href="#grammar-production-statement">statement</a></code> production produces a triple defined by the terms constructed for <code><a href="#grammar-production-subject">subject</a></code>, <code><a href="#grammar-production-predicate">predicate</a></code> and <code><a href="#grammar-production-object">object</a></code>. This RDF triple is added to the graph labeled by the production <code><a href="#grammar-production-graphLabel">graphLabel</a></code>, if no <code>graphLabel</code> is present the triple is added to the RDF datasets default graph.</p>
           </section>
 
 
         </section>
-      <section id="section-ack" class="informative" typeof="bibo:Chapter" resource="#section-ack" rel="bibo:chapter">
-        <!--OddPage--><h2 aria-level="1" role="heading" id="h2_section-ack"><span class="secno">6. </span>Acknowledgements</h2><p><em>This section is non-normative.</em></p>
+      <section id="section-ack" class="informative">
+        <h2>Acknowledgements</h2>
         <p>The editor of the 2013 edition acknowledges valuable contributions from Gregg Kellogg, Andy Seaborn, Eric Prud'hommeaux, Dave Beckett, David Robillard, Gregory Williams, Antoine Zimmermann, Sandro Hawke, Richard Cyganiak, Pat Hayes, Henry S. Thompson, Bob Ferris, Henry Story, Andreas Harth, Lee Feigenbaum, Peter Ansell, and David Booth.</p>
         <p>This specification is a product of extended deliberations by the 
         <a href="http://www.w3.org/2000/09/dbwg/details?group=46168&amp;public=1">members of the RDF Working Group</a> chaired by Guus Schreiber and David Wood. It draws upon the eariler specification in <em><a href="http://sw.deri.org/2008/07/n-quads/">N-Quads: Extending N-Triples with Context</a></em>, edited by Richard Cyganiak, Andreas Harth, and Aidan Hogan.</p>
       </section>
 
-      <section id="sec-changes" class="appendix" typeof="bibo:Chapter" resource="#sec-changes" rel="bibo:chapter">
-        <!--OddPage--><h2 aria-level="1" role="heading" id="h2_sec-changes"><span class="secno">A. </span>Changes to this document</h2><h2 id="generatedID">
-        </h2><h2 id="changes-since-last-publication-as-note">Changes since last publication as Note</h2>
+      <section id="sec-changes" class="appendix">
+        <h2>Changes to this document</h2><h2>
+        </h2><h3>Changes since last publication as Note</h3>
         <ul>
           <li>White space rules defined outside of grammar, as in Turtle.
           </li><li>Comment processing defined.
@@ -562,8 +670,8 @@
         </li></ul>
       </section>
 
-      <section id="sec-mediaReg" class="appendix" typeof="bibo:Chapter" resource="#sec-mediaReg" rel="bibo:chapter">
-        <!--OddPage--><h2 aria-level="1" role="heading" id="h2_sec-mediaReg"><span class="secno">B. </span>N-Quads Internet Media Type, File Extension and Macintosh File Type </h2>
+      <section id="sec-mediaReg" class="appendix">
+        <h2>N-Quads Internet Media Type, File Extension and Macintosh File Type </h2>
         <dl>
           <dt>Contact:</dt>
           <dd>Eric Prud'hommeaux</dd>
@@ -644,14 +752,4 @@
 
   
 
-<section id="references" class="appendix" typeof="bibo:Chapter" resource="#references" rel="bibo:chapter"><!--OddPage--><h2 aria-level="1" role="heading" id="h2_references"><span class="secno">C. </span>References</h2><section id="normative-references" typeof="bibo:Chapter" resource="#normative-references" rel="bibo:chapter"><h3 aria-level="2" role="heading" id="h3_normative-references"><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-EBNF-NOTATION">[EBNF-NOTATION]</dt><dd rel="dcterms:requires">Tim Bray; Jean Paoli; C. M. Sperberg-McQueen; Eve Maler; François Yergeau. <a href="http://www.w3.org/TR/REC-xml/#sec-notation"><cite>EBNF Notation</cite></a> 26 November 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/REC-xml/#sec-notation">http://www.w3.org/TR/REC-xml/#sec-notation</a> 
-</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119.  URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a> 
-</dd><dt id="bib-RFC3023">[RFC3023]</dt><dd rel="dcterms:requires">M. Murata; S. St.Laurent; D. Kohn. <a href="http://www.ietf.org/rfc/rfc3023.txt"><cite>XML Media Types (RFC 3023)</cite></a>. January 2001. RFC. URL: <a href="http://www.ietf.org/rfc/rfc3023.txt">http://www.ietf.org/rfc/rfc3023.txt</a>
-</dd><dt id="bib-RFC3986">[RFC3986]</dt><dd rel="dcterms:requires">T. Berners-Lee; R. Fielding; L. Masinter. <a href="http://www.ietf.org/rfc/rfc3986.txt"><cite>Uniform Resource Identifier (URI): Generic Syntax (RFC 3986)</cite></a>. January 2005. RFC. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a>
-</dd><dt id="bib-RFC3987">[RFC3987]</dt><dd rel="dcterms:requires">M. Dürst; M. Suignard. <a href="http://www.ietf.org/rfc/rfc3987.txt"><cite>Internationalized Resource Identifiers (IRIs)</cite></a>. January 2005. RFC. URL: <a href="http://www.ietf.org/rfc/rfc3987.txt">http://www.ietf.org/rfc/rfc3987.txt</a>
-</dd><dt id="bib-UNICODE">[UNICODE]</dt><dd rel="dcterms:requires"><a href="http://www.unicode.org/versions/latest/"><cite>The Unicode Standard</cite></a>. URL: <a href="http://www.unicode.org/versions/latest/">http://www.unicode.org/versions/latest/</a>
-</dd><dt id="bib-UTF-8">[UTF-8]</dt><dd rel="dcterms:requires">F. Yergeau. <a href="http://www.ietf.org/rfc/rfc3629.txt"><cite>UTF-8, a transformation format of ISO 10646</cite></a>. IETF RFC 3629. November 2003. URL: <a href="http://www.ietf.org/rfc/rfc3629.txt">http://www.ietf.org/rfc/rfc3629.txt</a>
-</dd></dl></section><section id="informative-references" typeof="bibo:Chapter" resource="#informative-references" rel="bibo:chapter"><h3 aria-level="2" role="heading" id="h3_informative-references"><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-UNICODE-SECURITY">[UNICODE-SECURITY]</dt><dd rel="dcterms:references">Mark Davis; Michel Suignard. <a href="http://www.unicode.org/reports/tr36/"><cite>Unicode Security Considerations</cite></a>. URL: <a href="http://www.unicode.org/reports/tr36/">http://www.unicode.org/reports/tr36/</a>
-</dd><dt id="bib-n-triples">[n-triples]</dt><dd rel="dcterms:references">Gavin Carothers. <a href="http://www.w3.org/TR/n-triples/"><cite>N-Triples</cite></a>. 9 April 2013. W3C Note. URL: <a href="http://www.w3.org/TR/n-triples/">http://www.w3.org/TR/n-triples/</a>
-</dd><dt id="bib-turtle">[turtle]</dt><dd rel="dcterms:references">Eric Prud'hommeaux; Gavin Carothers. <a href="http://www.w3.org/TR/turtle/"><cite>Turtle</cite></a>. 19 February 2013. W3C Candidate Recommendation. URL: <a href="http://www.w3.org/TR/turtle/">http://www.w3.org/TR/turtle/</a>
-</dd></dl></section></section></body></html>
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+</body></html>
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--- a/nquads/index.html	Tue Sep 03 19:56:29 2013 -0700
+++ b/nquads/index.html	Wed Sep 04 09:53:50 2013 -0700
@@ -171,6 +171,8 @@
               </ul>
       <p>A conforming <strong>N-Quad document</strong> is a Unicode string that conforms to the grammar and additional constraints defined in <a href="#sec-grammar" class="sectionRef"></a>, starting with the <a href="#grammar-production-nquadsDoc"><code>nquadsDoc</code> production</a>. A N-Quad document serializes an RDF dataset.</p>
 
+      <p class="note">N-Quad documents do not provide a way of serializing empty graphs that may be part of an RDF dataset.</p>
+
       <p>A conforming <strong>N-Quad parser</strong> is a system capable of reading N-Quad documents on behalf of an application. It makes the serialized RDF graph, as defined in <a href="#sec-parsing" class="sectionRef"></a>, available to the application, usually through some form of API.</p>
 
       <p>The IRI that identifies the N-Quad language is: <code>http://www.w3.org/ns/formats/N-Quads</code></p>