W3C home > Mailing lists > Public > semantic-web@w3.org > July 2012

Re: Why do we name nodes and not edges?

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 31 Jul 2012 09:57:17 -0500
Cc: トーレ エリクソン <tore.eriksson@po.rd.taisho.co.jp>, Hugh Glaser <hg@ecs.soton.ac.uk>, Melvin Carvalho <melvincarvalho@gmail.com>, Natasa Bulatovic <bulatovic@mpdl.mpg.de>, "<semantic-web@w3.org>" <semantic-web@w3.org>
Message-Id: <AB682C39-355A-4FF1-AA86-D89AEB62453E@ihmc.us>
To: Steve Harris <steve.harris@garlik.com>

On Jul 31, 2012, at 7:32 AM, Steve Harris wrote:

> On 2012-07-31, at 00:38, トーレ エリクソン wrote:
>> Hugh Glaser wrote:
>>> With respect to naming triples, at first sight it seems to me there is
>>> a perfectly sensible way of doing it, as I described in an earlier
>>> message. There is no need to describe a language for encoding the whole
>>> triple a unique URI for the edge uniquely identifies the triple, and
>>> seems quite natural.
>>> This URI can then be subPropertyOf whatever it would have been in the
>>> general form.
>>> So we have gained identifiers for triples for the possible maximum cost
>>> of one extra subPropertyOf triple for each triple to be identified.
>>> And now RDF can be used to make statements about each triple (edge), and
>>> I can do it all in Linked Data.
>>> This doesn't immediately solve the same thing as Named Graphs, where
>>> groups of triples/edges needed to be identified.
>>> But can't the edges be gathered into Classes?
>>> And with multiple inheritance, you can have arbitrary membership of
>>> Classes by any edge, giving much more power than simple Named Graphs,
>>> where triples/edges can only be members of one graph?
>> [snip]
>>> Is there anything technically wrong with what I am describing?
>> I find this solution quite intriguing as well. It would be easier to
>> implement if RDF were to allow blank nodes in the predicate position.
> You can't use bNodes (for fairly obvious semantic reasons)

Well, no. Actually there are no *semantic* problems with having bnodes in predicate position. The RDF semantics would adapt to this case quite smoothly. The same semantic constructions were used in ISO Common Logic which allows quantification over relations of arbitrary arity. Of course there might be other issues, but the semantics is OK.

> but you can put a genid URI (http://www.w3.org/TR/rdf11-concepts/#section-skolemization), or a UUID URN there, which has lots of the same benefits from a usability point of view, but without the bizarre mathematical implications.

What bizarre mathematics are you worried about? 


> - Steve
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Received on Tuesday, 31 July 2012 14:57:53 UTC

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