Scott, this is very helpful and I can see how SPARQL CONTRUCT would be
useful as yet another method of triple creation.

If there is a problem with my triple then there is an errata in the Allemang
& Hendler book because the triple is taken directly from the solution on
page 131.   I'll quote it here so that it may be useful to others:

> --------------quoted from book begin-----------------
> Since we want owl:inverseOf to work in both directions, this can be done
> easily by asserting that owl:inverseOf is its own inverse, thus:
>   owl:inverseOf owl:inverseOf owl:inverseOf .
>
> You might have done a double take when you read that owl:inverseOf is its
> own inverse.  Fortunately, we have a more readable and somewhat more
> understandable way to say this - namely:
>   owl:inverseOf rdf:type owl:SymmetricProperty .
> --------------quoted from book end-----------------
>

What I am trying to figure out is prior to this declaration, owl:inverseOf
only works one-way, after this is defined, owl:inverseOf will work in both
directions.

If I were to fererate across two respostiries where one of them redefined
the owl:inverseOf in this manner, it would be change at a global level.

--tk

On Wed, Dec 10, 2008 at 8:15 AM, Scott Henninger <[EMAIL PROTECTED]
> wrote:

>
> Hello;  There is a problem with your triple in that owl:inverseOf is a
> property and is used as the subject in "owl:inverseOf rdf:type
> owl:SymmetricProperty".  That's not allowed, so the redefinition
> couldn't happen.
>
> In addition, redefining rdf/rdfs/owl terms will not happen via
> inference.  You can extend these - for example creating a subproperty
> of rdfs:label.  And this is the intent of the Allemang & Hendler pages
> you cite.
>
> In general, though, inferencing can be aggressive and the ontology has
> to be designed with care.  This is one of the reasons TopQuadrant is
> spending resources to use SPARQL CONSTRUCT, for example, to provide
> infrastructure for more controlled "inferencing".  Take a look at
> http://spinrdf.org, which is part of these overall efforts.
>
> -- Scott
>
> On Dec 9, 6:15 pm, "tk blast" <[EMAIL PROTECTED]> wrote:
> > Hello fellow,
> > in the Allemang/Hendler book, on page 130-131 there is a discussion about
> > OWL to Extend OWL.
> > I want to make sure I understand the ramification of this type of
> assertion.
> >
> > If I were to import a file.owl that contained the triple:
> > owl:inverseOf rdf:type owl:SymmetricProperty .
> > it would redefine owl:inverseOf for all instances right?
> >
> > I guess what i am asking is when one goes about redefining items in the
> owl
> > namespace,
> > appropriate care must be given to the scope of those assertions.  Just
> like
> > rdfs:domain and rdfs:range, the inferences are aggresive and must be
> treated
> > with care.
> >
> > --tk
> >
> > --
> >
> > "The nervous system organizes itself so as to compute a stable reality" -
> > Maturana & Varela
> >
>


-- 

"The nervous system organizes itself so as to compute a stable reality" -
Maturana & Varela

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