Semantic links

Didier PH Martin martind at
Tue Jan 25 16:52:06 GMT 2000


Yes again, about links :-)) But this time about semantic links.

A link by itself is a kind of pointer. Can we make this pointer to provide
more information, like for instance meta data about the pointed resource?

I think that the answer is yes and that creating semantic links can lead to
more useful apps than the actual RDF.

Example of a semantic link:

<topic type="extended" title="XML">
	<resource type="locator" title="Everything you always wanted to know about
XML but where afraid to ask about" href="">
	`... other locators ....
	<description>resources about XML</description>
	<date>January 24 2000</date>
	<comment>put comments here...</comment>

So, if we have the same mechanism as RDF has for descriptions but this time
having all the properties enclosed in a "resource" element. Then, each
locator that points to a resource (this is its intent) can also provide meta
information about this resource. If the locator element is using the
"rdf:type" attribute, then the link can be related to a class hierarchy. The
class hierarchy could itself be part of a thesaurus and thus be included in
an ontology. So, an engine aware of xlink types and rdf types could:

a) know all the resources (one to many) that this link points and be able to
perform the operation required when the user select one of the anchors.
b) could provide to users semantic information by providing them meta data
about the resource.
c) Could relate the link to a certain ontology. For instance, if the link
having the title "XML" is also having the rdf:type="Markup". Then if the
rdf:schema is available (I still do not know how to relate the document to
the rdf schema), the engine may discover that the "markup" class is a
subclass of "text format" and then could propose to the user alternative
links knowing that an instance of class "markup" is also an instance of a
class "text format".

I found particularly useful the xlink:type attribute that allows me to
transform an element into a link (a kind of architectural form). The
rdf:type also because the engine can make semantic deductions like finding
that a "markup" entity is also a "text format" entity and thus go beyond the
link by adding more intelligence to navigation. Finally, I discovered that
if elements are included into "locators" as we would do for a
rdf:description frame, we also add meta data to the anchors and thus allow
the user to know what the resource is before navigating to it.

So these where the latest news from Didier's lab ;-) Anyway, I structure
this info in a more formal paper so that this recipe could also be used by

Didier PH Martin
Email: martind at
Conferences: Web New York (
Book to come soon: XML Pro published by Wrox Press

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at
Archived as: or CD-ROM/ISBN 981-02-3594-1
Unsubscribe by posting to majordom at the message
unsubscribe xml-dev  (or)
unsubscribe xml-dev your-subscribed-email at your-subscribed-address

Please note: New list subscriptions now closed in preparation for transfer to OASIS.

More information about the Xml-dev mailing list