W3C home > Mailing lists > Public > semantic-web@w3.org > May 2008

Re: {Disarmed} Re: Managing Co-reference (Was: A Semantic Elephant?)

From: Michael F Uschold <uschold@gmail.com>
Date: Thu, 15 May 2008 17:02:21 -0700
Message-ID: <406b38b50805151702x530da1e5jd16a57a116a48537@mail.gmail.com>
To: "Hugh Glaser" <hg@ecs.soton.ac.uk>
Cc: "Aldo Gangemi" <aldo.gangemi@cnr.it>, "Tim Berners-Lee" <timbl@w3.org>, "Sören Auer" <auer@informatik.uni-leipzig.de>, "Semantic Web Interest Group" <semantic-web@w3.org>, "Chris Bizer" <chris@bizer.de>, "Frank van Harmelen" <Frank.van.Harmelen@cs.vu.nl>, "Kingsley Idehen" <kidehen@openlinksw.com>, "Fabian M. Suchanek" <f.m.suchanek@gmail.com>, "Tim Berners-Lee" <timbl@csail.mit.edu>, "Jim Hendler" <hendler@cs.rpi.edu>, "Mark Greaves" <markg@vulcan.com>, "georgi.kobilarov@gmx.de" <georgi.kobilarov@gmx.de>, "Jens Lehmann" <lehmann@informatik.uni-leipzig.de>, "Richard Cyganiak" <richard@cyganiak.de>, "Frederick Giasson" <fred@fgiasson.com>, "Michael Bergman" <mike@mkbergman.com>, "Conor Shankey" <cshankey@reinvent.com>, "Kira Oujonkova" <koujonkova@reinvent.com>, "a.o.jaffri@ecs.soton.ac.uk" <a.o.jaffri@ecs.soton.ac.uk>, "icm@ecs.soton.ac.uk" <icm@ecs.soton.ac.uk>
Hugh Glaser said:

At the bottom you will se that an agent can import this as ntriples
owl:sameAs - we have nothing against owl:sameAs, if that is what the agent
wants to do, but the inference decision can be up to them.

This idea has a lot of merit, IMHO. It allows people a safe way to say that
URIs are closely related, w/o going so far is making them logically
equivalent.  And you offer a convenient way to convert the co-references to

This could make life a lot easier for folk who wish to load in a variety of
datasets and do reasoning on them.

Pity I won't make it to the upcoming workshop.


On Thu, May 15, 2008 at 11:59 AM, Hugh Glaser <hg@ecs.soton.ac.uk> wrote:

> Michael,
> Many thanks for asking the question.
> It is very exciting to see this discussion so active.
> I have been trying to get to the front of the messages to say something,
> but they just keep coming in!
> To answer you email:
> Yes, we have an infrastructure (the Consistent Reference Service, CRS) with
> which we have been trying to manage co-reference between a bunch of
> independent SW sites to allow applications to do what they need. It has gone
> through quite a few revisions over the last four years or so.
> On 15/05/2008 00:25, "Michael F Uschold" <uschold@gmail.com> wrote:
> Aldo notes the problems with using owl:sameAs to mean similarity. Such uses
> are often incorrect, and Aldo suggests using something like rdfs:seeAlso,
> skos:related, instead. These relations are too weak, unfortunately.
> There is an interesting proposal for managing URI snyonyms that attempts to
> have a middle ground, weaker than owl:sameAs, but much stronger than
> rdfs:seeAlso or skos:related.   They suggest an infrastructural approach
> [apparently] outside the logic for managing URI synonyms. It is a quite
> clever approach, but still has some challenges.  Here are portions of a note
> I just sent the authors of a paper, which relates to this question.
> Afraz, Hugh and Ian:
> I just read your workshop paper:
> Managing URI Synonymity to Enable Consistent Reference on the Semantic Web
> <http://eprints.ecs.soton.ac.uk/15614/1/camera-ready.pdf><
> http://eprints.ecs.soton.ac.uk/15614/1/camera-ready.pdf>
>  1.  I wholeheartedly agree that owl:SameAs is too strong in many cases. A
> weaker relation is needed. However, you don't offer weaker relation and give
> it semantics. Instead, you do a kind of sleight of hand and remove it from
> the logic.  Without  a semantics, what is a system developer to do with the
> fact that two URIs are in the same bundle?  What are the inferential
> impliciations?
>  2.
>  3.  Example: IMHO it is a bad idea to say that Spain the political entity
> is the same as Spain the geopolicial region. This ontological distinction
> has been clear documented in DOLCE, for example. They are different, and
> should have different URIs.  Conflating them will cause problems.  Of
> course, making this and many other ontologically 'sound' distinctions can
> cause its own problems, by adding complexity -- a tradeoff. Without any
> semantics of inCRS_Bundle, there is no way to tell if it is semantically
> correct.
>  4.  Do you have any idea of the scalability of this approach?
> Michael
> On Wed, May 14, 2008 at 2:24 PM, Aldo Gangemi <aldo.gangemi@cnr.it> wrote:
>       * Problem 2) even if you can find the links, prolific use of
> owl:sameAs will create computational problems.
> Michael,
> there is an item related to Problem 2), already discussed on LOD and
> elsewhere last year, i.e. the use of
> owl:sameAs, which is a formal relation of identity, to denote generic
> "similarity", or even "relatedness"
> between two entities.
> owl:sameAs is great to co-reference persons, places, etc. It is buggy when
> used to relate e.g. foaf:Person
> instances to persons' homepages, or a city as from Cyc to a wikipedia
> article of that city (as done in DBpedia).
> In previous discussions, besides some weak good practices [1], I found no
> attempt to discourage its use for similarity.
> This use is not needed. We can use e.g. rdfs:seeAlso, skos:related, or any
> other local relation instead.
> It is reasonable, as Richard Cyganiak wrote at the time, that we have to
> work around the quirks [2],
> nonetheless, if there is no real need, why should we work around the quirks
> caused by a pointless identity
> assumption?
> Notice that ignoring owl:sameAs is not a good solution. We need some
> trade-off between simplicity
> and formality. A basic similarity relation is perfect, and then those
> triples can be worked out automatically,
> by means of appropriate metamodels, e.g. as proposed in [3].
> Aldo
> [1] Bernard Vatant suggested some good practice of mutual linking:
> http://universimmedia.blogspot.com/2007/07/using-owlsameas-in-linked-data.html
> [2] Cyganiak quote:
> People who want to re-use your data will learn to work around its quirks
> and idiosyncrasies.
> Dealing with the quirks is a part of re-using data, it always was, and it
> always will be.
> [3] MailScanner has detected definite fraud in the website at "
> www.ibiblio.org". Do not trust this website:
> http://www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf <
> http://www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf><
> http://www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf>  from IRW workshop:
> MailScanner has detected definite fraud in the website at "www.ibiblio.org".
> Do not trust this website: http://www.ibiblio.org/hhalpin/irw2006/ <
> http://www.ibiblio.org/hhalpin/irw2006/><
> http://www.ibiblio.org/hhalpin/irw2006/>
> _________________________________
> Aldo Gangemi
> Senior Researcher
> Laboratory for Applied Ontology
> Institute for Cognitive Sciences and Technology
> National Research Council (ISTC-CNR)
> Via Nomentana 56, 00161, Roma, Italy
> Tel: +390644161535
> Fax: +390644161513
> aldo.gangemi@cnr.it
> http://www.loa-cnr.it/gangemi.html
> icq# 108370336
> skype aldogangemi
Received on Friday, 16 May 2008 00:03:07 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:42:04 UTC