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"equivalentTo" in DAML+OIL

From: Richard Fikes <fikes@KSL.Stanford.EDU>
Date: Wed, 18 Apr 2001 16:48:02 -0700
Message-ID: <3ADE27B2.B0FBE0BE@ksl.stanford.edu>
To: www-rdf-logic <www-rdf-logic@w3.org>
Another issue that emerged from my recent work on a DAML+OIL reasoner is
how to deal with the "equivalentTo" property.  I am aware that there has
been discussion of "equivalentTo" in the language committee, and I have
seen some of those messages.  I would like to add the following comment.

It seems that "equivalentTo" enables one to assert that any two
resources are equal, meaning that they denote the same object in the
domain of discourse.  I presume that means "equivalentTo" can be used to
assert that any two URIs are equal.

I am concerned as to what such a general-purpose equivalence property
means for reasoners.  It seems on the face of it that DAML+OIL reasoners
will need to do full reasoning with equality (using paramodulation?), an
unhappy thought.  For example, it seems that if a property has a
maxCardinality restriction of 1 at an object and the property has two
values V1 and V2 at the object, that a reasoner would need to conclude
that V1 is "equivalentTo" V2 rather than concluding that the
maxCardinality restriction had been violated.  Is that really what we
want?

Richard
Received on Wednesday, 18 April 2001 19:48:10 GMT

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