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Re: life without dataset semantics

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Wed, 19 Sep 2012 09:13:28 -0400
Message-ID: <5059C4F8.8040709@gmail.com>
To: Sandro Hawke <sandro@w3.org>
CC: David Wood <david@3roundstones.com>, "public-rdf-wg@w3.org Group WG" <public-rdf-wg@w3.org>
What do you think that the minimal semantics will get you?

So far, I've heard only one thing.  If g1 and g2 denote the same thing, then 
their graphs, if any, are put together (in essence). However, you can't do 
much of that kind of inference in RDF, so I don't think that there is much 
gain here.

In the example below, it seems to me that you can proceed exactly the same 
with the minimal dataset semantics, with no semantics at all, and with the 
entailment-only semantics.

peter


On 09/18/2012 07:22 PM, Sandro Hawke wrote:
> So, elsewhere you're proposing we not have dataset semantics.   I think I'm 
> okay with that, if I can still do what I'm trying to do here.      What I'm 
> not entirely clear on is how I can do this without any semantics....
>
> On 09/18/2012 02:10 PM, Peter F. Patel-Schneider wrote:
>>>
>>> Here's a much better example, because it stays away from Web stuff:
>>>
>>>     <g1> eg:sendCorrectionsTo <mailto:sandro@w3.org>.
>>>     <g1> { w3c:group35462 rdfs:label "SPARQL Working Group" }.
>>>     <g2> eg:sendCorrectionsTo <mailto:ivan@w3.org>.
>>>     <g2> { w3c:group44350 rdfs:label "RDFa Working Group" }.
>>>
>>>
>>> There's an obvious meaning to the predicate eg:sendCorrectionsTo, but how 
>>> do I express that meaning? Something like:
>>>
>>>     X eg:sendCorrectionsTo Y
>>>
>>>         Note: only meaningful inside a dataset which has a named graph with
>>>         the name X.
>>>
>>>         Meaning: Y is a good email address for sending corrections to the
>>>         information in the named graph X.
>>>
>>> Are you comfortable with that?
>>
>> I don't know if comfortable is the right word.  I don't have problems with 
>> anyone wanting to do that.
>
> My question is really: do you think that definition/documentation means what 
> I want it to and will work the way I want it to, if the RDF WG doesn't give 
> Datasets any semantics?
>
> That is, if the WG doesn't say anything about graph-name URIs connecting to 
> URIs as used in the default graph, can I just spell all that out (as above) 
> in the documentation of my predicate?
>
> And if I can't, then what alternative do I have for sharing this kind of 
> information structure?
>
>>   I can see that if this is the stance that someone wants to take with 
>> respect to named graphs, then one might want to have the relationship 
>> between IRIs and graphs work the way it works in the minimal semantics.
>>
>> However,  I don't think that everyone wants to have this connection.
>
> What I'm asking for is an extremely weak connection; it's hard for me to see 
> how it would do any harm, since it would only come into play when someone 
> ask for it.
>
>       -- Sandro
>
Received on Wednesday, 19 September 2012 13:14:00 GMT

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