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A thought on fragments and rec-track

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Thu, 14 Feb 2008 08:55:28 +0100 (CET)
To: public-owl-wg@w3.org
Message-id: <Pine.LNX.4.64.0802140842480.3269@frege.inf.tu-dresden.de>

Dear WG,

yesterday's discussion on fragments and rec-track showed once more
that, simplifying a lot, the WG is split into two groups. Let's call
them the RDF group and the DL group. Each of them has its own view and
valid arguments that support it. I believe that neither the WG nor the
two groups benefit from a confrontative way of dealing with this
situation.  Instead, we should try to have peaceful coexistence
whenever possible. Here is a simple way how this could be achieved for
the fragments/rec-track issue:

- We give OWL Full a rule-based semantics (it seems likely to me that
   this will be decided anyway)

- Then, there are two fragments in rec-track: one OWL-Full fragment
   (for the RDF group) and one OWL-DL fragment (for the DL group)

   So we have : OWL Full, OWL Full Minus , OWL DL, OWL DL Minus

   Never mind the naming scheme (IMHO, we should even rename OWL Full
   to OWL RDF).

- As OWL-Full Minus, we choose OWL Prime. Unless I overlook something,
   it is easily defined as a fragment of OWL-Full. Here, "fragment" means
   that it selects two things: a) a subset of the OWL-Full vocabulary
   and b) a subset of the OWL-Full semantic rules.

   This means that we do not need Boris' bright but complicated
   construction to capture OWL Prime as a syntactic fragment of OWL DL.
   Neither do we need conformance  levels (but we could still have them
   if we want).

- As OWL DL Minus, we choose a real *syntactic* fragment, as this is what
   the DL group seems to imagine. I think this must be EL++, and am
   happy to again provide motivation for why this is the case, and what
   are the serious and commercial applications. But in general, that's
   another issue.

- All the other fragments also remain, but don't go into rec-track.

greetings,
 		Carsten

PS: As for OWL 1.0 Lite, I suggest that we don't make it rec-track any-
     more, but explain in rec-track why this is the case and that OWL 1.0
     Lite users are now simply OWL 1.1 DL users, and thus fully supported.
     This is what I understood Alan was proposing. I don't view the issue
     of punning as problematic.

--
*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Thursday, 14 February 2008 07:55:50 GMT

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