RE: LC responses 28, 48 & 58

>-----Original Message-----
>From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
>Sent: Wednesday, March 11, 2009 1:00 AM
>To: Michael Schneider
>Cc: public-owl-wg@w3.org
>Subject: Re: LC responses 28, 48 & 58

>> [[
>> OWL 2 separates syntax from semantics, and that OWL 2 Full,
>> DL, QL, EL and RL are all refer to syntactic variants,
>> ]]
>>
>> Frankly, this makes no sense to me. OWL 2 Full is certainly not a
>"syntactic
>> variant", just as OWL 1 Full hasn't been.
>
>OWL 2 Full is all ontologies / all RDF graphs.  A syntactic variant.

If "OWL 2 Full" means the set of all RDF graphs, then the term 
is redundant.

In this case, and if "OWL Full" was also intended to be used 
in that way, then "OWL 2 Full" would be the same as "OWL Full" 
(and any "OWL N Full" in the future). I cannot make much sense 
of this.

If, however, "OWL Full" was /not/ meant to be understood in this
way (and this is how I read the original spec), then I do not
see any justification for changing this view in OWL 2. 

>This matches the wording in the last paragraph of Section 2.3 of the
>Document Overview but not that earlier in the Section.  I have proposed
>changes to the Document Overview in my next message.
>
>> In the OWL 1 Full spec, there existed semantic-related terms like "OWL
>Full
>> interpretation" and "OWL Full entails". And OWL Full was characterized
>as
>> follows in a semantic way:
>>
>> <http://www.w3.org/TR/owl-semantics/rdfs.html#5.3>
>> [[
>> OWL Full augments the common conditions with conditions
>> that force the parts of the OWL universe
>> to be the same as their analogues in RDF.
>> [...]
>> ]]
>>
>
>And, as Ian says, this story is being changed slightly.

I don't believe that Frank and the other commenters asked for such a change:

<http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0035.html>
[[
Hence, we strongly insist that the names are adjusted to be in
line with common practice.
]]

And from their comments it's hard for me to foresee that they will accept such a change to happen. I'm fearing that we are on a dangerous path here. Changes on /that/ level (e.g. the meaning of the basic names) will be relevant even to parties that generally aren't too interested in technical details, I guess.

>> "OWL 2 Full" exclusively to mean the /semantics/.
>
>I argue against this.

And so do I. I want to see "OWL 2 Full" to mean the whole language, not 
just a single component of it, i.e. neither only semantics, 
nor only syntax. That's what I believe is "common practice".
Of course, not only for "OWL Full", but for all the names.

But if you disagree, then there is an easy way to find out: 
Just let's ask the public what they think the term "OWL DL" 
refers to: Only the syntax, only the semantics, or the whole 
language consisting of both syntax and semantics?

Or, as a start: Just let's ask Frank what he means by "common practice",
because he wasn't particularly clear on this, IMHO. 

>I'm quite willing to abuse the notation and let OWL 2 Full mean
>ontologies under the RDF-Based Semantics as well as just a syntax, just
>as I would let OWL 2 DL mean ontologies that meet the syntactic
>characterisation of OWL 2 DL under the Direct Semantics as well as just
>a syntax.

That's certainly appropriate and common in practice. But if I am 
being asked by confused people what I precisely mean by the term 
"OWL 2 DL", only the syntax or the language as a whole, then there 
is no doubt that I will answer that I mean the whole language 
(syntax + semantics).

Just as I would answer for virtually every other language that I am 
aware of. People may claim that they only mean the syntax when they 
talk about C++. But the C++ ISO consortium will definitely tell them 
that the whole language is meant, not just the syntax. And, I guess, 
if a textbook does otherwise, it will receive a lot of feedback, or 
eventually none at all... :)
 
And, in fact, the syntax and semantics of C++ do not have own names,
they are only called something like "C++ syntax" and "C++ semantics". 
Are there any other languages, which have special names for their 
syntax and their semantics, as in OWL 2? Actually, in OWL 2 
the situation is even more peculiar, since the concrete languages 
in the OWL 2 family do not even have own names (officially)! We 
currently have to talk about 

  "the language that has 
   OWL 2 DL as its syntax 
   and the OWL 2 Direct Semantics as its semantics"

Doesn't this bother anyone else then me?

FWIW, whatever our decision will be, I will, whenever I am talking to
my colleagues or to FZI's technological partners or industrial customers, 
ALWAYS call this whole language "OWL 2 DL", and the syntax will be the 
"OWL 2 DL syntax", and the semantics will be the "OWL 2 DL semantics". 
I would consider everything else to be confusing, to say the least.
 
>Note that part of the OWL 2 DL syntactic conditions have been chosen
>only to allow for mapping into and out of RDF - these conditions are not
>necessary to achieve the semantic and computational benefits of OWL 2
>DL.
>
>> But Jonathan Rees had a comment on this:
>>
>> http://lists.w3.org/Archives/Public/public-owl-
>comments/2009Jan/0068.html
>> [[
>> And are you sure that you want "OWL 2 Full" to be the name of a
>semantics?
>> That seems OK to me, but it's sort of weird.  In common use I think it
>> will be taken to mean a language consisting of a combination of syntax
>> (RDF in any of its serializations) and
>> semantics (conditions on interpretation of the OWL 2 vocabulary).
>> ]]
>>
>> This sounds reasonable to me, so I am strongly inclined to follow this
>> comment. The term "OWL 2 Full" would then mean the whole language. But
>not
>> the syntax alone. This would make no sense to me, because the syntax
>of OWL
>> 2 Full is RDF, just as for OWL 1 Full and RDFS.
>
>Well, I would argue that the true language of OWL 2 Full is the
>Structural Specification. 

I'm afraid, I won't adopt this particular view.

>The RDF serialisation is just something that
>fits better into the current preferred Semantic Web story.
>
>> Best,
>> Michael
>
>peter

Michael

--
Dipl.-Inform. Michael Schneider
Research Scientist, Dept. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: michael.schneider@fzi.de
WWW  : http://www.fzi.de/michael.schneider
=======================================================================
FZI Forschungszentrum Informatik an der Universität Karlsruhe
Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
Tel.: +49-721-9654-0, Fax: +49-721-9654-959
Stiftung des bürgerlichen Rechts, Az 14-0563.1, RP Karlsruhe
Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael Flor,
Prof. Dr. Dr. h.c. Wolffried Stucky, Prof. Dr. Rudi Studer
Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
=======================================================================