On 2010/7/1 22:42, Kingsley Idehen wrote:
Pat Hayes wrote:
On Jun 30, 2010, at 3:49 PM, Kingsley Idehen wrote:
Pat Hayes wrote:
On Jun 30, 2010, at 1:30 PM, Kingsley Idehen wrote:
Nathan wrote:
Pat Hayes wrote:
On Jun 30, 2010, at 6:45 AM, Toby Inkster wrote:
On Wed, 30 Jun 2010 10:54:20 +0100
Dan Brickley <dan...@danbri.org> wrote:
That said, i'm sure sameAs and differentIndividual (or however
it is
called) claims could probably make a mess, if added or removed...
You can create some pretty awesome messes even without OWL:
# An rdf:List that loops around...
<#mylist> a rdf:List ;
rdf:first <#Alice> ;
rdf:next <#mylist> .
# A looping, branching mess...
<#anotherlist> a rdf:List ;
rdf:first <#anotherlist> ;
rdf:next <#anotherlist> .
They might be messy, but they are *possible* structures using
pointers, which is what the RDF vocabulary describes. Its just
about impossible to guarantee that messes can't happen when all
you are doing is describing structures in an open-world setting.
But I think the cure is to stop thinking that possible-messes
are a problem to be solved. So, there is dung in the road. Walk
round it.
Could we also apply that to the 'subjects as literals' general
discussion that's going on then?
For example I've heard people saying that it encourages bad
'linked data' practise by using examples like { 'London' a
x:Place } - whereas I'd immediately counter with { x:London a
'Place' }.
Surely all of the subjects as literals arguments can be countered
with 'walk round it', and further good practise could be aided by
a few simple notes on best practise for linked data etc.
IMHO an emphatic NO.
RDF is about constructing structured descriptions where "Subjects"
have Identifiers in the form of Name References (which may or many
resolve to Structured Representations of Referents carried or
borne by Descriptor Docs/Resources). An "Identifier" != Literal.
What ARE you talking about? You sound like someone reciting doctrine.
Literals in RDF are just as much 'identifiers' or 'names' as URIs
are. They identify their value, most clearly and emphatically. They
denote in exactly the same way that URIs denote. "23"^^xsd:number
is about as good an identification of the number twenty-three as
you are ever likely to get in any notational system since ancient
Babylonia.
Yes, but ancient Bablyonia != World Wide Web of Structured Linked
Data, slightly different mediums with some shared characteristics :-)
The World Wide Web is becoming a Distributed DBMS (in my eyes).
Thus, unambiguous naming matters.
A topic for a longer discussion; but irrelevant here, since typed
literals are as unambiguous as a name can possibly get.
Literal Subjects aren't a "show stopper" per se. (esp. for local RDF
data). My gripe simply boils down to the nuisance factor introduced
by data object name ambiguity in a distributed data object oriented
realm such as the emerging Web of Linked Data.
What does ""23"^^xsd:number " mean to anyone in a global data space?
It means the number twenty-three, everywhere and for all time,
because this meaning can be computed from the very syntactic form of
the name. How unambiguous can something get?
Pat,
Re. RDF's triples, What is a Subject? What is an Object?.
If they are the same thing, why on earth do we use Names (with
implications) to describe the slots in an RDF triple?
I've only once seen the RDF triple referred to as O-R-O (by @danbri)
i.e., Object-Relation-Object.
In addition, I don't see Information and Data as being the same thing.
Information (as I know it) is about Data + Context. Raw Data (as I
know it) is about: a unit of observation and deemed worthy of
description by its observer. You have to give Names to subject of a
description. "23"^^xsd:number isn't a Name.
**
I guess my own subtle mistake (re. this thread) is deeming Identifiers
and Names to be equivalent , when they aren't :-) Of course, one can
use an Identifier as a Name, but that doesn't make them equivalent.
**
One clear point of divergence here is that I am focused on the Web as
Dist. DBMS that leverages 3-tuples + HTTP URIs in the S, P, and
optionally O slot (aka. HTTP based Linked Data).
To conclude:
Name != Identifier.
We can also question the role of URI. Because the location of resource
pointed by URI and the content of URI are orthogonal. A location is
interpreted by a set of locating operations, the locating result is
only GUIDED, not CONTROLLED, by the content of URI. To realize this is
very important!
regards
Peng
I believe Subject == Name (an Identifier based Name) re. RDF triples
otherwise the triple should be described as: O-R-O or O-P-O.
I believe an S-P-O triple is a piece of information (Data Object has a
Name and at least one Attribute=Value pair).
What I desscribe actually has zilch to do with RDF as I am inclined to
believe you see RDF :-) Thus, in a way, the literal-subject debate may
simply help everyone understand and accept that RDF != Linked Data.
Thus, providing additional proof that RDF isn't mandatory or even
required re. delivery of HTTP based Linked Data.
RDF based Linked Data != RDF. They are different things, clearly. We
can't have it both ways (** Pat: not for you, that's for those that
deem RDF and Linked Data inextricably linked **).
BTW - I still have no idea if RDF and RDF/XML are really distinct.
HTML and N3 built the Web of Linked Data, but N3 remains a 2nd or 3rd
class citizen whenever we talk about the pragmatic aspects of what
continues to be inappropriately labeled as an RDF virtue i.e. Linked
Data.
Danbri:
I agree with the essence of your earlier post!
Kingsley
Pat
I know the meaning of:
<http://km.aifb.kit.edu/projects/numbers/web/n23#this>, based on the
resource I deref at: <http://km.aifb.kit.edu/projects/numbers/web/n23>
Kingsley
Pat Hayes
If you are in a situation where you can't or don't want to mint an
HTTP based Name, simply use a URN, it does the job.
Best,
Nathan
--
Regards,
Kingsley Idehen President & CEO OpenLink Software
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen
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Regards,
Kingsley Idehen President & CEO OpenLink Software Web:
http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen
------------------------------------------------------------
IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St. (850)202 4416 office
Pensacola (850)202 4440 fax
FL 32502 (850)291 0667 mobile
phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
