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Re: rev and the costs of inverses/aliases in SPARQL

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Mon, 8 Mar 2010 16:16:28 +0000
Message-Id: <6C1E4DB7-AFFE-4911-8D06-390F11507FD7@cs.man.ac.uk>
Cc: public-sparql-dev <public-sparql-dev@w3.org>, public-rdfa <public-rdfa@w3.org>
To: Dan Connolly <connolly@w3.org>
On 8 Mar 2010, at 15:00, Dan Connolly wrote:

> I just ran into this message again from an HTML 5 validator:
> "The rev attribute on the a element is obsolete. Use the rel attribute
> instead, with a term having the opposite meaning."

Note that this is the OWL 1 situation (i.e., must coin a name to have  
an inverse). OWL2 has an operator as do most DLs directly.

just having fought with an RDFa example:

<a  about='owl:Class' rev="rdf:type" href='http://www.pizzas- 
	<span property='rdfs:label'>Momma's Special Pizza</span>

I did find the rev confusing (I was starting from someone else's;  
href's behavior is annoying in this case).

> Doesn't that just gum up the works when doing SPARQL queries? Which
> do you query for, abridgement or abridgementOf? Or do you use
> a UNION?

Or add the requisite rule/owl axiom.
> Would the RDFa authoring community miss a/@rev if it went away?
> Does anyone have 1st-hand experience to share?

I would miss the inverse operator in OWL (esp. in class expressions).  
Dunno if I'd miss rev.

One thing that seems to be the case in my brief foray is that being  
too clever is bad and will bite you hard. The above example is too  
clever. I should have done something like:

<a href='http://www.pizzas-online.org/pizza-ontology.owl#rosa'>
	<span rel="rdf:type" resource="owl:Class"/>
	<span property='rdfs:label'>Momma's Special Pizza</span>

So, at least from this example, not only would I not miss rev, but I  
would have avoiding going down a wrong path.

Received on Monday, 8 March 2010 16:16:26 UTC

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