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Re: Why do we name nodes and not edges?

From: Danny Ayers <danny.ayers@gmail.com>
Date: Thu, 26 Jul 2012 11:05:20 +0200
Message-ID: <CAM=Pv=QnjHT2VNANFuLpbXMxBLOdtBftA9-5VfL9THJUjpQv5w@mail.gmail.com>
To: Melvin Carvalho <melvincarvalho@gmail.com>
Cc: Steve Harris <steve.harris@garlik.com>, Dave Reynolds <dave.e.reynolds@gmail.com>, semantic-web@w3.org
Tractability. Having the predicate/property bits shared (comparable to
static classes) means any reasoning you want to do over them gets
easier (I'm not sure, but flexible predicates probably means flipping
beyond FOL).

Pragmatically, if you have a different URI in the middle, how are you
going to query against it?

Cheers,
Danny.

On 25 July 2012 18:11, Melvin Carvalho <melvincarvalho@gmail.com> wrote:
>
>
> On 25 July 2012 18:08, Steve Harris <steve.harris@garlik.com> wrote:
>>
>> Yes, exactly, I was writing in a bit of a hurry, maybe a UUID would make
>> made it clearer.
>
>
> Thanks for the responses, is there a standard way to encode
>
> "triple"
>
> into
>
> urn:uuid:triple?
>
> (For the sake of convenience, let's assume we are not dealing with bnodes)
>
>>
>>
>> - Steve
>>
>> On 2012-07-25, at 17:04, Dave Reynolds wrote:
>>
>> > If I understand Steve's point he was meaning that you can mint a new
>> > unique edge:xxxxxx identifier for each edge.
>> >
>> > [Presumably you could make that a subPropertyOf the actual property you
>> > wanted to assert.]
>> >
>> > Cheers,
>> > Dave
>> >
>> > On 25/07/12 16:47, Aidan Hogan wrote:
>> >> Steve,
>> >>
>> >> If I understand Melvin's point, in RDF, edge:123456 is the URI of a
>> >> property used to label the edge, not the edge itself.
>> >>
>> >> Analogously, you don't identify a class-instance by it's class URI.
>> >>
>> >> An edge is between two things. It might be directed and it might be
>> >> labelled. In RDF it's both.
>> >>
>> >> Hence, the edge would encapsulate the full triple, including source
>> >> (subject) and target (object) nodes, as well as the label (predicate).
>> >>
>> >> Cheers,
>> >> Aidan
>> >>
>> >> On 25/07/2012 16:18, Steve Harris wrote:
>> >>> Nothing stops you from giving edges a unique URI, infact I think I've
>> >>> worked on systems that did that.
>> >>>
>> >>> e.g.
>> >>>
>> >>> <foo> <http://example.com/edge/123456> 1 .
>> >>> <http://example.com/edge/123456> a rdf:Property .
>> >>> ...
>> >>>
>> >>> - Steve
>> >>>
>> >>> On 2012-07-25, at 16:07, Melvin Carvalho wrote:
>> >>>
>> >>>> Sorry if this topic has been covered before, but I have a question
>> >>>> based on the axioms of the web, in particular:
>> >>>>
>> >>>> *Axiom 0a: Universality 2    Any resource of significance should be
>> >>>> given a URI.
>> >>>> *
>> >>>> In this case we consider the web to be a directed graph (of nodes and
>> >>>> edges), where a *node* corresponds to a *resource* but edge does not.
>> >>>>
>> >>>> We are encouraged to make nodes universal by giving them a URI.
>> >>>>
>> >>>> Why dont edges get the same treatment, ie encouragment to give it a
>> >>>> (universal) name.  Is it even practical?
>> >>>>
>> >>>> I know there's such thing as reification but that seems to be
>> >>>> unpopular (maybe before my time).
>> >>>>
>> >>>> I'm just curious as to whether this seems asymmetrical, that nodes
>> >>>> are
>> >>>> seemigly treated in one way, and edges in another?
>> >>>
>> >>> --
>> >>> Steve Harris, CTO
>> >>> Garlik, a part of Experian
>> >>> +44 7854 417 874 http://www.garlik.com/
>> >>> Registered in England and Wales 653331 VAT # 887 1335 93
>> >>> Registered office: Landmark House, Experian Way, Nottingham, Notts,
>> >>> NG80 1ZZ
>> >>>
>> >>
>> >>
>> >
>> >
>>
>> --
>> Steve Harris, CTO
>> Garlik, a part of Experian
>> +44 7854 417 874  http://www.garlik.com/
>> Registered in England and Wales 653331 VAT # 887 1335 93
>> Registered office: Landmark House, Experian Way, Nottingham, Notts, NG80
>> 1ZZ
>>
>>
>



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Received on Thursday, 26 July 2012 09:05:55 UTC

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