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Least-damage approach to @href/@resource completing triples

From: Manu Sporny <msporny@digitalbazaar.com>
Date: Wed, 09 Jan 2008 21:31:16 -0500
Message-ID: <47858374.9000608@digitalbazaar.com>
To: RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>

First, I do believe that Mark's approach is the proper way to do things
from a programming/engineering/graph theory perspective.

Everybody that I've heard explain RDF/N3 have said that a triple is:

SUBJECT PREDICATE OBJECT .

If we assume that people will understand that @about/@href/@resource can
be used to set the subject OR object (depending on whether or not you're
chaining), then there are no issues. Unfortunately, I don't think many
will understand that rather advanced concept until they've been immersed
in RDFa for several months. The danger is: What happens if people don't
understand that?

My initial thought on "accidental" triple generation was: "Too bad,
that's what the markup states. They'll get burned, they'll learn and
they'll fix their markup. They should learn how to use RDFa properly.
They should understand what they're typing."

Ben's rules makes it harder to generate triples accidentally, as well as
simplifying what can/can't generate a triple. This is at the cost of
slightly more verbose markup and a compromise on orthogonality between
what @about/@src/@href/@resource can do.

Mark's rules are very powerful and @about/@src/@href/@resource are quite
orthogonal. In a way, they are simpler to explain... but harder to truly
grasp without a basic understanding of graph theory. You can express
things very succinctly, the danger being that you might generate
something you didn't mean to.

Mark Birbeck wrote:
> So no-one is proposing an alternate model to mine, they are just
> suggesting that some of the formulations that my model enables should
> be prescribed.

In that case, perhaps we can look at the issue assuming that the
decision we are about to make is going to be disastrous.

Scenario #1: We go with Mark's rules. Ben is right. Spurious triples
             are generated on a widespread scale, HTML markup must be
             changed drastically to incorporate RDFa.

Outcome: Bloggers start unknowingly creating a large volume of spurious
triples that express the wrong relationships, thinking that they
understand which triples they are creating. They don't check their work,
they're lazy. The semantic web becomes a sea of triples... half are
correct, half are absolutely wrong.

How do we fix it: Replace Mark's rules with Ben's rules in RDFa 2.0...
all of a sudden tons of triples disappear off of web pages (because
people will probably just change the DOCTYPE at the top of the page - or
people are using tag-soup parsers). The publishers that were using
Mark's rules properly are very annoyed that they just sporadically lost
3 years worth of triples - they don't know which ones they lost because
it is impossible to check automatically.

Scenario #2: We go with Ben's rules. Mark is right. Publishers have a
             much harder time expressing semantics succinctly using
             RDFa.

Outcome: Triples aren't being generated because blogger's aren't using
the proper markup. Bloggers complain that RDFa is difficult to use
because @href/@resource don't do what is expected... it's also too
verbose, adoption is slow.

How do we fix it: Education and tools that generate the proper triples.
If we have to, Ben's rules are replaced with Mark's rules in RDFa 2.0.
However, we will have a ton of real-world use cases to see if Mark's
rules would actually help or hurt matters at that point.

So, while I partially agree with Mark's approach, I can't support it
because of the two disaster scenarios I've outlined above. Ben's rules
are going to be less harmful in the long run if we're wrong. Most
importantly, the semantic web can recover from Ben's rules.

If there is a place to be cautious about "accidental" triple generation,
it is in version 1.0 of RDFa.

And if people complain about not being able to use @href/@resource to
complete a triple, we have a great answer for them:

 "Then you're going to love the @href/@resource upgrade in RDFa v2.0!"

                                 :)

-- manu

-- 
Manu Sporny
President/CEO - Digital Bazaar, Inc.
blog: Intro to the Semantic Web in 6 minutes (video)
http://blog.digitalbazaar.com/2007/12/26/semantic-web-intro
Received on Thursday, 10 January 2008 02:31:22 GMT

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