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Re: Profiles intro

From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
Date: Thu, 10 Apr 2008 10:15:09 +0200 (CEST)
To: Ivan Herman <ivan@w3.org>
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, OWL Working Group WG <public-owl-wg@w3.org>
Message-id: <Pine.LNX.4.64.0804101002350.27195@frege.inf.tu-dresden.de>

Hi Ivan,

here are some responses to your text, of course representing only my
own view of things.

> [[[
> In some cases, the emphasis is on possibly very large concept hierarchies and 
> the corresponding queries, rather than on sophisticated characterizations of, 
> and with properties (roles). EL++ is a profile where such queries can be 
> responded in polynomial time.

Hmm. The term "concept hierarchies" sounds too weak for what you can
do with EL++. Indeed, you *can* relate classes in terms of properties
in EL++ (also in OWL-R, only not in DL Lite). EL++ is a true ontology
language and can do much more than describing hierarchies. For
example, it *does* have sophisticated facilities for talking about

Also the term "queries" seems misleading here since it sound
like querying of data. I would rather speak of classification and
similar services that are central for ontologies.

> In other cases, the emphasis is to provide a minimal classification and 
> federation vocabulary over a possibly very large set of data (typically in 
> the form of RDF triplets), while maintaining efficient querying. Two such

DL Lite seems unrelated to RDF triplets. It is only OWL-R that is very

> profiles are defined: DL-Lite, that can be implemented on top of traditional 
> database systems using query rewriting, and OWL-R, that can be implemented 
> using basic rule systems.
> ]]]


> I hope this is at least factually correct. It is interesting to note that on 
> such high level there is no real difference between DL-Lite and OWL-R, and 
> the only way to differentiate them on that level is how they are implemented. 
Yes, a main difference between DL-Lite and OWL-R is implementation
techniques. Another one is maybe RDF-ishness.

> I also believe that the names of the profiles should somehow reflect the high 
> level characterization. Something like:
> EL++     -> OWL HI (for hierarchies?)

I would be very unhappy with this. As noted above, this sounds very weak
given what EL++ can actually do.

> DL Lite  -> OWL DB

Sounds reasonable. But is Zhe happy with this? One of the main reasons
d'etre for OWL-R seem to be the implementation in DBs with rules.

> OWL-R    -> OWL Rules

There is a chance of misinterpretation here.  Namely, there is a lot
of work on combining OWL with rule-based formalisms (aren't some of
them even called "OWL Rules"?), and this is very different from
*implementing* an OWL profile using rules. In general, are these
names reflecting the typical use of a profile or a technique supported
by the profile? Not so clear to me.

In general, the naming issue is very difficult. I am not sure whether
it is a good idea to reflect the use of the fragments in their name,
as this is very suggestive and may be misleading (and people may find
interesting uses for the profiles that we never thought of).


*      Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden       *
*     Office phone:++49 351 46339171   mailto:lutz@tcs.inf.tu-dresden.de     *
Received on Thursday, 10 April 2008 11:17:17 UTC

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