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Re: concerns about RDF Mapping doc

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Mon, 22 Oct 2007 08:49:52 -0400 (EDT)
Message-Id: <20071022.084952.62238336.pfps@research.bell-labs.com>
To: jjc@hpl.hp.com
Cc: public-owl-wg@w3.org

[I'm picking on a particular point that Jeremy is making here, and thus
I am only quoting part of his message.]

From: Jeremy Carroll <jjc@hpl.hp.com>
Subject: Re: concerns about RDF Mapping doc
Date: Mon, 22 Oct 2007 13:29:17 +0100

[...]

> *****
> The role of the mapping rules is to allow interoperability between OWL 
> DL and OWL Full - this is crucial in avoiding a schism in the semantic web.

[...]

> Every AST in OWL DL is mapped into a graph in OWL Full with the 'same 
> meaning'.

This is true for many OWL DL KBs, but not all.

> Given a graph g in OWL Full, which has the same meaning as some AST in 
> OWL DL, it is not too difficult to find a related graph g' for which 
> there is some tree t' which maps to g'.
> 
> There are some not too complicated rules of thumb that can be used when 
> constructing such a g that ensure that g=g' nearly all of the time.

I am rather skeptical of this claim.  Consider, for example, any graph
that shares syntax, e.g., where parts of the graph that correspond to
bits of the mapping of OWL DL syntax, particularly restrictions, are
used multiple times.  Such graphs are not the mapping of any OWL DL KB.
I would think that any non-trivial OWL DL KB will have multiple bits of
recurring syntax, each providing a non-unary multiplicative factor to
the number of non-mapping graphs that are 'equivalent' to the OWL DL KB.

[...]

> Jeremy

peter
Received on Monday, 22 October 2007 12:59:47 GMT

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