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Re: [ALL] agenda telecon 14 Dec

From: Dan Brickley <danbri@danbri.org>
Date: Wed, 14 Dec 2011 17:23:14 +0100
Message-ID: <CAFNgM+b6rNsvOzT8TZ2HmT3LL_w854WTUGNv4_-TU_NqS_r5qQ@mail.gmail.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
Cc: public-rdf-wg@w3.org
On 14 December 2011 09:25, Andy Seaborne <andy.seaborne@epimorphics.com> wrote:
>
>
> On 13/12/11 22:20, Dan Brickley wrote:
>
>> It's tempting to try to use this standardisation opportunity to
>> squeeze something like Gremlin/Tinkerpop's 'Property graphs" into RDF,
>> ie. something like
>> https://github.com/tinkerpop/gremlin/wiki/Defining-a-Property-Graph in
>> which graph edges are decorated with little extras. But I can't really
>> see a route to getting there...
>>
>> Dan
>>
>
> That would be an n-ary property, with two of the parties of the n-ary
> relationship slightly distinguished as subject and object? (not sure they
> are distinguished - it might be just the way you look at the graph)

Yes this is the most interesting design point.

When you talk to people about RDF, only having binary relations often
causes frustration. There's a desire to qualify relations in various
ways.

I've wondered before about saying "OK, RDF 2.0 isn't binary, but
n-ary.". Which would be weird for many people who someone see binary
relationships as being the absolute core of the RDF project. So why
isn't RDF n-ary? My take is because this would be pretty hard to do
with all the messy open-world-ism of Web data.

If I remember right from Pat, CommonLogic deals with this by having
every arity of a predicate be technically a different predicate.

So you might have an RDF-esque ''worksWith'/2, or maybe a
'worksWith'/5 where the extra slots are used for notions of 'from',
'to', 'role' etc. The problem there is what to do when they're
missing. Is the simpler version implied by the richer version always?

The TinkerPop annotated graph style I think does suggest a model in
which all the decorations are explicitly subsidiary, and can 'drop
off'; any graph with extras, when stripped of those extras, should
still be true. And that's what would allow us to have different extras
in different contexts and have the freeform mess still interoperate.

Not entirely convincing myself, but hopefully clarifying,

Dan
Received on Wednesday, 14 December 2011 20:31:29 GMT

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