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Re: category theory

From: Renato golin <renato@ebi.ac.uk>
Date: Mon, 09 Jul 2007 10:48:27 +0100
Message-ID: <4692046B.7050308@ebi.ac.uk>
To: Ivan Herman <ivan@w3.org>
CC: semantic-web@w3.org

Ivan Herman wrote:
> However... what type of results/research would you expect to see out of
> that? I could very vaguely see some possibilities in looking at
> structural equivalence and analysis of RDF graphs, but I am not sure
> that would reveal anything significant  (I may be wrong!). I am also not
> sure that, say, the concept of injection or surjection would give
> anything new with respect to what OWL can already describe in terms of
> functional and inverse functional properties...
> I am interested to hear/see which way you want to go with that.

Hi Ivan,

I'm not an expert in OWL and RDF but I've been looking for a particular 
behaviour on some ontologies (dc, rdf, rdfs, etc) and couldn't find 
(what doesn't mean it's not there).

Some relationships are injective:
	"Luke, I'm your father"

It means that Darth Vader is Luke's father but not the other way around.

Other relationships are bijective:
	"Reuben is Stitch's cousin"

Which means also that Stitch is Reuben's cousin.

Some relation are neither exactly:
	"I love her"

Who said that hope it to be bijective, but it might be not.

We understand all three sentences but a program will not, unless you 
specify those relationships to it. I mean, a program cannot know that 
Luke is Vader's son just reading that phrase (unless previously 
hard-coded in the program, but that's what we're trying to avoid with 
RDF I guess).

But if you say that, not only that father is injective but that there is 
an opposite and the opposite is son, voilá. If it was bijective, the 
program wouldn't look for the opposite for it'd know they're the same.

So, when I ask the program: "Who is Reuben's cousin?" it'll know that 
it's Stitch.

At last, when asked who loves me it should say: "She might love you, let 
me check" and go through the RDF jungle, searching for quotes from "her" 
saying she loves me... or not.

The third case require further enquires, on data that might not be 
available (for she's a bit shy) but the first two, by adding the 
additional category constraint, I can rely on the data itself.

Maybe there is a way already to do it using the current ontologies...

Received on Monday, 9 July 2007 09:48:36 UTC

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