Implement ISSUE-40 resolution by adding section on skolemization plus some wording tweaks
authorRichard Cyganiak <>
Wed, 25 May 2011 17:43:59 +0100
changeset 10 db6de57fcb4f
parent 9 24c9dbb622a7
child 11 9d286f508d41
Implement ISSUE-40 resolution by adding section on skolemization plus some wording tweaks
--- a/ReSpec.js/bibref/biblio.js	Wed May 25 16:49:37 2011 +0100
+++ b/ReSpec.js/bibref/biblio.js	Wed May 25 17:43:59 2011 +0100
@@ -1,6 +1,7 @@
 berjon.biblio = {
 // @@@ These are temporary local additions for rdf-concepts; they should be either removed (many are obsolete) or added to the global file in CVS
+// Old stuff from 1.0
    "RFC2279" : "<a href=\"\"><cite>RFC 2279 - UTF-8, a transformation format of ISO 10646</cide></a>, F. Yergeau, IETF, January 1998. This document is",
    "RFC2396" : "<a href=\"\"><cite>RFC 2396 - Uniform Resource Identifiers (URI): Generic Syntax</cite></a>, T. Berners-Lee, R. Fielding and L. Masinter, IETF, August 1998. This document is",
    "RFC2732" : "<a href=\"\"><cite>RFC 2732 - Format for Literal IPv6 Addresses in URL's</cite></a>, R. Hinden, B. Carpenter and L. Masinter, IETF, December 1999. This document is",
@@ -8,6 +9,8 @@
    "IRI-DRAFT" : "<a href=\"\"><cite>Internationalized Resource Identifiers (IRIs)</cite></a>,  M. D&uuml;rst and M. Suignard, Internet-Draft, June 2003, expires December 2003. This document is",
    "TAG" : "<a href=\"\"><cite>TAG Issues List</cite></a>,  W3C Technical Architecture Group. This document is",
    "RDF-MIME-TYPE" : "<a href=\"\"><cite>MIME Media Types</cite></a>, The Internet Assigned Numbers Authority (IANA). This document is .  The <a href=\"\">registration for <code>application/rdf+xml</code></a> is archived at .",
+// New stuff
+   "WELL-KNOWN" : "M. Nottingham; E. Hammer-Lahav. <a href=\"\"><cite>Defining Well-Known Uniform Resource Identifiers (URIs).</cite></a> April 2010. Internet RFC 5785. URL: <a href=\"\"></a>",
    "ABC" : "Leo Geurts; Lambert Meertens; Steven Pemberton. <a href=\"\"><cite>The ABC Programmer's Handbook.</cite></a> Prentice-Hall. ISBN: 0-13-000027-2. URL: <a href=\"\"></a>",
    "ABNF" : "D. Crocker and P. Overell. <a href=''><cite>Augmented BNF for Syntax Specifications: ABNF.</cite></a> January 2008. Internet RFC 5234. URL: <a href=''></a>",
--- a/index.html	Wed May 25 16:49:37 2011 +0100
+++ b/index.html	Wed May 25 17:43:59 2011 +0100
@@ -408,10 +408,10 @@
     <p>A <a>blank node</a> is a node that is
     not a URI reference or a literal. In the RDF abstract syntax, a
     blank node is just a unique node that can be used in one or
-    more RDF statements, but has no intrinsic name.</p>
+    more RDF statements.</p>
     <p>A convention used by some linear representations of an RDF
-    graph to allow several statements to reference the same
-    unidentified resource is to use a <dfn>blank node
+    graph to allow several statements to use the same
+    blank node is to use a <dfn>blank node
     identifier</dfn>, which is a local identifier that can be
     distinguished from all URIs and literals. When graphs are
     merged, their blank nodes must be kept distinct if meaning is
@@ -1187,6 +1187,46 @@
 Given two blank nodes, it is 
 possible to determine whether or not they are the same.</p>
+<section id="section-skolemization">
+    <h4>Replacing Blank Nodes with IRIs</h4>
+    <p>Blank nodes do not have identifiers in the RDF abstract syntax. The
+    <a title="blank node identifier">blank node identifiers</a> introduced
+    by some concrete syntaxes have only
+    local scope and are purely an artifact of the serialization.</p>
+    <p>In situations where stronger identification is needed, systems MAY
+    systematically transform some or all of the blank nodes in an RDF graph
+    into IRIs [[!IRI]].  Systems wishing to do this SHOULD mint a new, globally
+    unique IRI (a <dfn>Skolem IRI</dfn>) for each blank node so transformed.</p>
+    <p>This transformation does not change the meaning of an RDF graph,
+    provided that the Skolem IRIs do not occur anywhere else.</p>
+    <p>Systems may wish to mint Skolem IRIs in such a way that they can
+    recognize the IRIs as having been introduced solely to replace a blank
+    node, and map back to the source blank node where possible.</p>
+    <p>Systems that want Skolem IRIs to be recognizable outside of the system
+    boundaries SHOULD use a well-known IRI [[WELL-KNOWN]] with the registered
+    name <code>genid</code>. This is an IRI that uses the HTTP or HTTPS scheme,
+    or another scheme that has been specified to use well-known IRIs; and whose
+    path component starts with <code>/.well-known/genid/</code>.
+    <p>For example, the authority responsible for the domain
+    <code></code> could mint the following recognizable Skolem IRI:</p>
+    <pre></pre>
+    <p class="note">IETF registration of the <code>genid</code> name is
+    currently in progress.</p>
+    <p class="note">RFC 5785 [[WELL-KNOWN]] only specifies well-known URIs,
+    not IRIs. For the purpose of this document, a well-known IRI is any
+    IRI that results in a well-known URI after IRI-to-URI mapping [[!IRI]].</p>
@@ -1444,6 +1484,7 @@
   <h2>Changes since First Edition</h2>
+    <li>2011-05-25: Implemented resolution of <a href="">ISSUE-40: Skolemization advice in the RDF dcocument</a> by adding a section on <a href="#section-skolemization">Replacing Blank Nodes with IRIs</a></li>
     <li>2011-05-25: rdf:XMLLiteral is disjoint from any datatype not explicitly related to it, per erratum <a href="">[concept-xmlliteral]</a></li>
     <li>2011-05-25: Added Conformance section with RFC2119 reference</li>
     <li>2011-05-25: Updated all W3C references to latest editions, and Unicode from v3 to v4</li>