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Re: RDF* semantics

From: Olaf Hartig <olaf.hartig@liu.se>
Date: Fri, 30 Aug 2019 08:29:20 +0000
To: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
CC: thomas lörtsch <tl@rat.io>
Message-ID: <6124989.umiClIOb9Y@porty3>
Hi Thomas,

On torsdag 29 augusti 2019 kl. 10:18:48 CEST thomas lörtsch wrote:
> [...]
> Ah, you are really taking all those little ’that’ words very serious ;-)

I better do; we are talking about semantics here ;-)

> [...] your translation, "a person Bob who is of age 23", captures the sense
> of factualness even better.

Good.

> > Therefore, all the triples together seem to say that a person named
> > Alice claims a person named Bob who is of age 23. My initial example
> > said something else, namely: person Alice claims *that* person Bob is of
> > age 23.
> 
> Hmm, that *that* again ;-) So you mean the difference between Alice claiming
> that there exists a "Bob, person, aged 23" and Alice claiming that some
> already introduced and agreed upon person Bob is "aged 23"?

While the fact that the person Bob has already been introduced and agreed upon 
is necessary to make single-statement claims about this person, this is 
secondary to the main point I keep on trying to make. Again, in my opinion, 
Kingsley's data cannot be interpreted as you do in your sentence above (person 
Alice claims "that there exists" a person Bob of age 23). In contrast, since 
bnode _:b2 represents 'a person Bob of age 23', the :claims triple with _:b2 
in the object position is to be interpreted as: person Alice claims the person 
Bob (rather than claiming the existence of such a person). Hence, the verb 
"claim" here is used with its meaning of demanding ownership instead of its 
meaning of stating (potentially false) facts. See:

https://en.wiktionary.org/wiki/claim#Verb


If you would only want to capture that person Alice claims "that there exists" 
a person Bob of age 23, then the object of the :claims triple cannot be the 
bnode _:b2, but instead the object needs to be a graph that contains the three 
triples that have bnode _:b2 in their subject position. 

> Technically that is the difference between talking about a set
> of triples with the same subject (lines 4-6 in the above example) and a
> single triple (line 6), right?

Almost. See above.

Best,
Olaf


> >> [...]
> >> However I would also like to stress that such modelling is not
> >> meta-modelling and it is not equivalent to a layer of abstraction
> >> (vulgo taking one step back) like reification or named graphs.
> > 
> > Exactly! That's the point I am trying to make with this example. To
> > capture the statement that "Alice claims *that* Bob is of age 23," we
> > need a form of meta-modeling.
> 
> And I just wanted to express my endorsement of your position in that
> respect.
> >> [...]
> >> Well, as I’m on it, a shameless plug: I recently posted an unhaelthily
> >> long mail to this list . That mail started with [...] I wonder if anybody
> >> bothered to read that sermon.
> > 
> > I did ;-)
> 
> Great! :-)
> 
> > ...and I was planning to respond to it. However, since I am on this list
> > here in my spare time, I couldn't get to it right away.
> 
> No pressure! ;-)
> 
> Thomas
> 
> > Olaf


Received on Friday, 30 August 2019 08:29:56 UTC

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