The RelRDF HTML Profile

Contents: Briefly | An Example

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Briefly

Use of the string "http://www.w3.org/2002/12/RelRDF" as an HTML profile signals that the HTML document uses certain syntactic and semantic conventions described below.

These conventions allow absolute URI-References to be used in the rel attribute on "a" elements to link pages in an RDF-compatible manner. (There are some possible differences from how you might interpret RDF semantics; I've been trying to clarify that in RDF, as in my e-mails of 2002-12-13 and 2002-12-23. I'm confident I have the right meanings at this end, but there's a lot of history of using HTTP URIs in overloaded ways.

When absolute URIRefs are given as values for rel attributes, the document is taken to assert:

  1. The document itself has a single predominant subject (call it N1)
  2. The document or document fragment linked to by the "href" attribute has a single predominant subject (call it N2)
  3. The document or document fragment identified by the rel attribute's value has a single predominant subject (call it P)
  4. P is an RDF property
  5. The RDF triple <N1, P, n2> is true

Whether or not the identified documents or document fragments are actually available or intelligible not change the essential meaning here. What's important is how the web addresses stand in relation to some arbitrary thing.

An Example

Here's an example namespace document:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head profile="http://www.w3.org/2002/12/RelRDF">
<title>The "L" Namespace</title>
</head><body>

<h1>The Example-L Namespace</h1>

<p>This document addresses the <a 
href="http://lists.w3.org/Archives/Public/www-tag/2002Nov/0147>RDDL 
Challenge</a></p>

<p>If you are using the Example-L namespace, you may be interested in
  <a rel="http://www.rddl.org/purposes#validation" 
     type="http://relaxng.org/ns/structure/1.0"
     href="http://example.com/schemas/L.rng">a RelaxNG schema</a>
and
  <a rel="http://www.rddl.org/purposes#render" 
     type="text/css"
     href="http://example.org/style/L.css">a very terse style sheet</a>
</p>
</body></html>

which you can also see directly.

This work is being done as part of the MIT/LCS DAML Project under the MIT/AFRL cooperative agreement number F30602-00-2-0593. This work is not on the W3C recommendation track and is not the product of a W3C working group or interest group.

Sandro Hawke
First: 2002-12-24; This: $Date: 2002/12/24 17:57:06 $