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Re: possible way forward on ISSUE-69 (1.1/Full punning) and ISSUE-72 (backwards comptability)

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Thu, 24 Jan 2008 21:27:48 -0500
Message-Id: <AD4E28AF-05FC-46C5-B930-53F3B74E69F9@cs.rpi.edu>
Cc: public-owl-wg@w3.org
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Hmm, trying to decide what I think about this - if I open an OWL 1.0  
ontology written in the normative exchange syntax (i.e. OWL/RDF),  
then how does a tool decide if it is in OWL 1.1 DL or not if the  
functional-style syntax is normative?  Does that mean we must have a  
mechanism for mapping all of the OWL 1.0 stuff into the new syntax  
just to see if it is legal?   There are a number of deployed  
ontologies in OWL 1.0 and at least some of the current tools (like  
Swoop) can open them and then tell the user what OWL sublanguage they  
are in (Lite, DL or Full) and in some cases, what would be needed to  
move into DL for use with a DL reasoner.  If we make the OWL DL 1.1  
normative syntax be the functional-syntax, wouldn't we lose this?  
(i.e. when we so called "round trip", what would be round tripping  
to, as there'd be no normative RDF format for DL if we go with the  
   It may come as a surprise to some, but I might not oppose this -  
at this point, I'm thinking that if OWL DL necessarily lives in a  
different syntax and is unmistakable for RDF, then OWL DL will be  
able to go into the market that has accepted previously deployed DL  
languages, and the deployers of RDF tools will no longer need to  
worry about compatibility with OWL DL -- we could also change the  
layer cake to have OWL DL sitting on XML, and only OWL Full would  
need to sit on RDF/RDFS, which would be closer to the truth than the  
current layer cake-- in fact, we could remove "with Semantic Web  
basis" from the subtext of OWL DL below, and this whole thing would  
make more sense... (yes, yes, Alan I know I'm not being positive here  
- but frankly, I'm not sure a divorce between DL and Full wouldn't be  
better than the very uncomfortable marriage that seems to be evolving.)

On Dec 13, 2007, at 11:40 AM, Peter F. Patel-Schneider wrote:

> There has been discussion on compatibility between OWL 1.1 DL and OWL
> Full as well as backwards compatibility between OWL 1.1 DL and OWL 1.0
> DL.
> I propose the following solution, which defines what we want for
> compatability as well as changing DL in line with the practice of
> existing DL reasoners.  (Changes are marked with *.)
> OWL Full: RDF extension
> - Normative syntax is RDF graphs.
> - Normative semantics is an extension of RDFS Semantics with
>   extra semantic conditions on RDF(S) and OWL vocabulary.
> - Any RDF graph is a valid "input".
>   - Some RDF graphs are ontologies,
>     - namely those that ... owl:Ontology.
>   - It is expected that inputs will be ontologies.
> OWL DL: Ontology Language with Semantic Web basis
> - Normative syntax is the functional-style syntax.
> - Normative semantics is the DL-style semantics.
> - Only ontologies that meet all requirements of FS syntax are allowed,
>   - including the non-local requirements related to simple roles.
> * Annotations are not allowed on the right-hand side of entailments.
>   - This fixes the problem noted in ISSUE-72 at the expense of  
> limiting
>     what sort of questions can be asked in OWL DL.
> Relationship between the two views:
> 1/ There is a translation T from the functional-style syntax to RDF
>    triples.
> 2/ If O, O' are valid LHS and RHS for OWL DL entailment
>    then O |= O' in OWL DL implies that T(O) |= T(O') in OWL Full
>    - This is the current relationship between OWL DL and OWL Full,  
> where
>      there are more entailments in OWL Full than in OWL DL.
>      It allows for punning, defining how OWL DL and OWL Full are  
> allowed
>      to relate in this area.
> Desirable backward-compatibility property:
> 1/ If O, O' are valid LHS and RHS for OWL 1.1 DL entailment
>    and O |= O' in OWL 1.0 DL iff T(O) |= T(O') in OWL 1.0 Full
>    then O |= O' in OWL 1.1 DL iff T(O) |= T(O') in OWL 1.1 RDF
>    - This says that we keep exact correspondence whereever possible.
> Peter F. Patel-Schneider
> Bell Labs Research

"If we knew what we were doing, it wouldn't be called research, would  
it?." - Albert Einstein

Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair
Computer Science Dept
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Friday, 25 January 2008 02:28:40 UTC

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