3rd Draft response to LC comment 30 (FH4)

Based on the comments of Bijan and Christine on the list, and some other
discussion with Ian and Alan, here is a slightly reworded version of the
answer.

I think the discussion on the rationale of choosing a new syntax (ie,
replacing the AS) was actually useful in improving our documents...

Ivan

-------------------------

Dear Frank,

Thank you for your comment

<http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0037.html>
on the OWL 2 Web Ontology Language last call drafts.

We also note the 'addendum' to your original comment in

http://lists.w3.org/Archives/Public/public-owl-comments/2009Feb/0014.html

And we thank you for helping us avoiding further confusion on this issue.

Indeed, as you note in your second mail, the current Functional Syntax
(FS) notation uses the _:x syntax to denote anonymous individuals.

Concerning the usability of AS in OWL 2: if used as an exchange syntax
then, of course, OWL 1 ontologies written in AS may be input to OWL 2
tools and remain valid ontologies. But we must emphasize that this is an
issue of the tool providers: the only _required_ exchange syntax for OWL
2 ontologies being RDF/XML, it is up to the tools to decide whether they
would accept ontologies serialized in AS (or in FS, for that matter).

There were several motivations of changing from the OWL 1 abstract
syntax (AS) to the OWL 2 FS. First of all, several readers actually
found the implicit blank nodes of the AS quite confusing. In general,
the new syntax is in closer correspondence with RDF graphs, to make it
clearer that anonymous individuals are in direct correspondence with
blank nodes. For example, one can refer to anonymous/blank nodes from
more than one place, hence a larger class of RDF graphs can be expressed
in FS.

The FS is also closer to the syntax used in first order logic, which
makes various specification issues as well as relating OWL 2 abstract
constructs to the general literature easier. As the primary role of the
FS is to _define_ the structure of OWL 2 (and not necessarily to serve
as a serialization syntax), the clarity of the syntax was an important
factor for choosing it.

We agree this isn't made very clear in the documents, and we will try to
improve the presentation. For example, we plan to add some explanatory
text into the New Features and Rationale document on the change of syntax.

We hope this answers your concerns on this particular issue.

Please acknowledge receipt of this email to
<mailto:public-owl-comments@w3.org> (replying to this email should
suffice). In your acknowledgment please let us know whether or not you
are satisfied with the working group's response to your comment.

Regards,
Ivan Herman
on behalf of the W3C OWL Working Group


-- 

Ivan Herman, W3C Semantic Web Activity Lead
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