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Re: [TF-ENT] RDFS entailment regime proposal

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Fri, 25 Sep 2009 15:20:31 +0100
Message-ID: <492f2b0b0909250720p6dad642t1cf7476ae7f1b9d1@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
I got the message :-)

2009/9/25 Ivan Herman <ivan@w3.org>:
> Hi Birte,
>
> (I hope you will get this message...)
>
> - I have a question v.a.v. your first design alternative, ie, excluding
> axiomatic triples from the set of query answers. If my data has a
> container, ie, I do have
>
> ex:A rdf:_1 ex:Q .
>
> in my data and I use the query
>
> WHERE { ?x rdf:type rdf:Property. }
>
> does it mean that I will not get back a ?x->rdf:_1 mapping? After all,
>
> rdf:_1 rdf:type rdf:Property .
>
> is an axiomatic triple and the way I understood what you wrote this
> would be excluded.

Yes. If we exclude allaxiomatic triples, it does not matter whether it
occurs in your data or not. That option assumes that you "know" the
axiomatic triples and that they always follow. It is not the design
option that I have chosen, but it is another alternative. My currently
prefered option would return ?x->rdf:_1, but not ?x->rdf:_2 unless
rdf:_2 occurs somewhere in your data.

> I may misunderstand something but if this is the case, I do not think I
> like it:-(

That is good to know. It is not my favourite choice either, but I
thought I mention it as an option. Once I have some more feedback,
I'll either remove the design choice options and stick to my choice or
change my choice if it seems that there is a better way to do it that
I overlooked or there is a majority of people who like another way of
doing it.

> - I concur with your remark that the second alternative is fairly
> unintuitive...

Yes, the only nice thing about is that it has a more monotonic
bahavior and monotonicity is really a nice feature that ideally every
query language should have IMO, but here it comes certainly at a
price...

> Bottom line: I think I like the choices you _did_ make:-) (unless I
> misunderstood your first design alternative...

I think you uderstood it.

> Cheers
>
> Ivan
>
> P.S.1: Would it be possible to transfer this wiki page to the Working
> Group Wiki? There were some trivial misspelling and my fingers were
> itching to change those, but, well, you guys are not on the Group pages...

I should have CVS access soonish and I thought I move all that is in
WebOnt to the CVS. Would that help or should we maintain a wiki page
too? I have not yet seen what is in the CVS, will it show up in the
wiki too?

> P.S.2 As an aside, you may want to look at [1] to see if that is a
> problem with your mails.
>
> [1] http://lists.w3.org/Archives/Member/chairs/2009JulSep/0080.html

I think my change to the config file helped. I rather get some spam
than having to unspam a lot of important mails and recieve them with
delays...

Birte

> Birte Glimm wrote:
>> Hi all,
>> whoever is interested in RDFS entailment: I would be very happy about
>> comments and suggestions for the RDFS entailment regime as outlined
>> in:
>> http://wiki.webont.org/page/SPARQL/OWL
>>
>> Ignore the OWL part for now. It is not at all finished and will
>> certainly change! Axel, can you check whether that would work with
>> what you have in mind for RIF? My RIF knowledge is far too limited to
>> judge that :-(
>>
>> There are a view design choices that I have listed at the end of the
>> section on RDFS, which could be an alternative to the currently
>> proposed way of restricting the answers sets to a finite size. Please
>> let me know prefer any of them or have any other suggestions. Ideally,
>> a monotonic behavior for queries would be very nice, but that is not
>> easy to achieve when solution sequences are possibly infinite without
>> restrictions.
>>
>> I would like to get access to the CVS and work in a real template. Who
>> can arrange that?
>>
>> Cheers,
>> Birte
>>
>> PS: Our email server is still behaving strangely regarding W3C
>> messages and I do not even get my own messages, so I might get your
>> answers with some delay only :-(
>>
>
> --
>
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
>



-- 
Dr. Birte Glimm, Room 306
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283529
Received on Friday, 25 September 2009 14:21:07 GMT

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