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Re: semantics of daml:equivalentTo [was: Comments on Annotated DAML 1.6]

From: Jeff Heflin <heflin@cs.umd.edu>
Date: Thu, 12 Oct 2000 15:29:56 -0400
Message-ID: <39E61134.1181E2A1@cs.umd.edu>
To: www-rdf-logic@w3.org
I'd just like to elaborate on Jim's message. I believe that equivalentTo
is the DAML version of the SHOE <DEF-RENAME> element. In SHOE,
DEF-RENAME allows an ontology to provide an alias for a term defined
elsewhere. Essentially, it means that both terms reference the same
concept, and thus any assertion that is made using one term is also true
if the other term was substituted in its place. This is really easy to
implement: you keep a hash table that matches aliases with the base
terms (used in the original definitions) that they renamed, and upon
parsing a document or issuing a query you can perform the necessary
substitutions to rephrase it in only base terms.

Because of the confusion that equivalentTo has caused on this list,
perhaps "renames" or "aliasOf" are better choices for the propery name?

Jeff

> 
> While I'm not a details guy like Dan, I thought the definition of
> equivalency was a simple one (i.e. not actually equality) -- I
> thought we were striving for essentially "macro" like replacement --
> i.e. if (equiv XXX YYY) then it should mean replacing XX with YYY
> leaves meaning unchanged.  This may seem silly, but consider it where
> one ontology has something called "automobile" and another has
> something called "car" -- I may want some agent to know it can map
> between these two so I would want to be able to assert that
> ontology1:autombile is equivalent to ontology2:car.  Jeff Heflin and
> Sean Luke introduced this to the SHOE language, and it was quite
> useful (and they can correct me if I haven't explained it well) --
> Jeff's versioning work (see the SHOE web page) also uses this.
>   -Jim H.
> 
> Dr. James Hendler               jhendler@darpa.mil
> Chief Scientist, DARPA/ISO      703-696-2238 (phone)
> 3701 N. Fairfax Dr.             703-696-2201 (Fax)
> Arlington, VA 22203             http://www.cs.umd.edu/~hendler
>
Received on Thursday, 12 October 2000 15:29:58 GMT

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