W3C home > Mailing lists > Public > www-rdf-logic@w3.org > February 2001

RE: universal languages

From: Miles Sabin <MSabin@interx.com>
Date: Sun, 4 Feb 2001 00:13:34 -0000
Message-ID: <23CF4BF2C499D411907E00508BDC95E116FBDB@ntmews_01.interx.com>
To: www-rdf-logic@w3.org
Dan Brickley wrote,
> Griping about RDF 1.0 being simplistic misses the point. The 
> Web is simplistic; if this agent language we're discussing on 
> RDF-Logic is going to work, it's going to have to work with, 
> for, and on the Web. Content authoring and management tools 
> will need built-in support for creating and editing expressions 
> in this language. And that's where the usability issues bite.
> Object-related-to-Object is a nice simple conceptual model. You 
> could teach it to school kids. While there are many reasons for 
> wanting n-ary, you lose the immediacy that comes with binary 
> relations.

I wasn't griping about core RDF being simplistic. On the contrary
I think that, for all that core RDF is lacking in some important 
respects, what's there is overly complex and baroque. Neither am 
I objecting to triples or binary relations ... they're perfectly 
appropriate for some tasks, of course. But I don't think you can 
claim that they're the simplest or most natural primitive units 
(which isn't to say that I think that there's anything else which 
would be more simple or natual in _all_ cases).

To take up your example of teaching it to school kids ... I guess
you'd probably want to take them through something like the
introductory example from RDF M&S ... you'd show them how to
assert of their webpages that they were the authors, and show
them how to make various assertion about themselves. Kids being
kids, they'd probably want to assert of themselves 'I'm a girl'
or 'I'm a boy'. Intuitively they'd want to write things like,

  <s:Person about="...">
    <s:Name>Little Joey</v:Name>
    <s:Email>joey@school.edu</v:Email>
    <s:Boy/>
  </s:Person>
    
[Is that empty element legal? A strict reading of RDF M+S
 Basic RDF serialization form [6] suggests not, but I'll assume
 that it is and that it's equivalent to <s:Boy></s:Boy>]

Now get them to draw the graph representation of this corpus
and watch their dear puzzled little faces as they try and work 
out what the object of the third assertion is.

Of course you might just tell them that they shouldn't do it
that way, and should instead have written,

  <s:Gender>Female</s:Gender>

or,

  <s:Gender>Male</s:Gender>

But _why_ should they have to do that? What are these mysterious
gender literals that they're related to? Is this _really_ the
simplest and most natural way of representing unary predicates?

To be sure, you could give them a crash course in RDF Schema and
rdfs:subPropertyOf or rdfs:subClassOf (being careful to skirt
around the vexed question of whether or not the class of girls 
and the class of boys are disjoint). But then it's far from clear 
that we've still got the 'nice simple conceptual model' you were
claiming at the outset.

Cheers,


Miles

-- 
Miles Sabin                               InterX
Internet Systems Architect                5/6 Glenthorne Mews
+44 (0)20 8817 4030                       London, W6 0LJ, England
msabin@interx.com                         http://www.interx.com/
Received on Saturday, 3 February 2001 19:14:20 GMT

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