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Re: life without dataset semantics

From: Sandro Hawke <sandro@w3.org>
Date: Wed, 19 Sep 2012 09:40:43 -0400
Message-ID: <5059CB5B.6030209@w3.org>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
CC: David Wood <david@3roundstones.com>, "public-rdf-wg@w3.org Group WG" <public-rdf-wg@w3.org>
On 09/19/2012 09:13 AM, Peter F. Patel-Schneider wrote:
> What do you think that the minimal semantics will get you?

I'm kind of in the crossfire here.   I'm not arguing for the minimal 
semantics.   I'm happy with no semantics/any semantics, as long as I can 
do my sendCorrectionsTo example (quoted below).   In my implementation 
work in the spring I came to the conclusion that all I need to implement 
all the GRAPHS use cases that I understood was the ability to define 
predicates like that.

> 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.

You're probably right.    There are just semantic bits in defining 
sendCorrectionsTo that I'm kind of confused about, like whether it makes 
sense to define an RDF property that only has meaning when it's used in 
a dataset.   That's a little weird; maybe there's a better way to define it?

        -- Sandro

> 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 13:41:00 UTC

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