Re: equivalentTo

From: Jim Hendler (
Date: 03/21/01

At 3:00 PM +0000 3/21/01, Dan Brickley wrote:
>On Wed, 21 Mar 2001, Peter F. Patel-Schneider wrote:
>  > Hi:
>  >
>  > As I was going through the reference document last night, I again
>  > encountered the issue of equivalentTo.
>  >
>  > equivalentTo has been used to make two things the same.  [...]
>"make two things the same"
>You mean they weren't the same previously? (I'm assuming you don't)
>ps. re your main point; I agree. That said, I'm tempted to punt on
>generic 'equivalentTo' and just stick with specific uses (eg. 
>utility properties
>to say that two classes have the same extension...)

I think equivalento is arguably the most important DAML function for 
the semantic web, and I would hate to see it go.  I want to be able 
to assert that

EquivalentTo URI1:XXX URI2:YYY

So that I can have translation files for my agents when they go from 
ontology to ontology.  I want this to be an automated function, so 
I've been hacking an applet that lets me view ontologies (using an 
RDF grapher that I think Dan C wrote) and assert equivalences by 
clicking on the graphs.  Since I, as the user, don't know whether I'm 
necessarily looking at classes, properties or instances, it is very 
simple for my applet to just assert equivalentTo.  (I leave it to a 
later device to fix the fact that I may have done something illegal - 
like making a class and a property equivalent - or immoral - like 
creating an inconsistency).  While I could do some sort of analysis 
to determine if these things were properties, classes, etc - it is 
easier not to, and I'm sure I'm not the only lazy tool developer out 

p.s. Having said all that, the applet code is minimal and likely not 
to be completed until after my life at DARPA -- I really was just 
trying to prove to myself it was possible...

Dr. James Hendler
Chief Scientist, DARPA/ISO	703-696-2238 (phone)
3701 N. Fairfax Dr.		703-696-2201 (Fax)
Arlington, VA 22203

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