W3C home > Mailing lists > Public > public-owl-wg@w3.org > January 2009

Response to Andy Seaborne's comments on rdf:text

From: Jie Bao <baojie@cs.rpi.edu>
Date: Wed, 14 Jan 2009 12:21:58 -0500
Message-ID: <b6b357670901140921j4be87090h76df1d20a00878d6@mail.gmail.com>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: "Sandro Hawke" <sandro@w3.org>, "Axel Polleres" <axel.polleres@deri.org>, "Boris Motik" <boris.motik@comlab.ox.ac.uk>, "W3C OWL Working Group" <public-owl-wg@w3.org>

Hi Andy

Thank you for your comment [1] on rdf:text [2]. Here is some my
personal opinion on the issues you described. Other authors of the
document may have further comments.

Summary: In short, I believe your concern in mainly on the
compatibility between rdf:text and the current specifications
including RDF and SPARQL. I agree that rdf:text should not change the
current specifications, explicitly or implied, nor have an impact on
the behavior of existing tools that are designed to handle RDF. The
wording of rdf:text should be changed to make this position clear. On
the other hand, other syntaxes of OWL and RIF, without legacy issues,
should be required to use rdf:text.

===========

"Issue 1: systems that do understand rdf:text may represent
information in RDF in two different ways that other RDF systems not
upgraded to rdf:text will interpret in two different ways."

I agree with your proposal that an RDF/XML implementation must
abbreviate "xyz@lang"^^rdf:text into "xyz"@lang. In fact, Sandro had
similar thoughts in a previous mail [3], which matches my belief so
well that I quote it below

"For simplicity of implementation, I think RDF serializations should
mandate use of one style of language tagging or the other.  In order to
handle legacy syntaxes which were created before rdf:text and so could
not pick, I think we should probably say rdf:text SHOULD NOT be used in
any RDF syntax which has built-in support for language tagging (in order
to avoid all the problems you name, below).

That is, in RDF/XML, N-Triples, N3, and Turtle, one SHOULD NOT use
rdf:text.  (Happily, this aligns with rdf-syntax saying "Any other names
are not defined and SHOULD generate a warning when encountered, but
should otherwise behave normally.")  Meanwhile, the various RIF syntaxes
and the newer OWL syntaxes do not directly support language tagging, so
one has to use rdf:text.  Perhaps a Turtle 1.1 would remove type-a
language tagging and mandate rdf:text instead.  Similarly, APIs are free
to pick one or the other (or some other, equivalent) approach, but
should probably just provide one, and certainly not distinguish between
the two."

Thus, I propose to
* make the two changes you suggested for this issue
* add the following text to the end of the 1st paragraph of section 3.

<A language syntax that does not directly support language tagging by
RDF's plain literal with language tags, including but not necessarily
limited to other OWL and RIF syntaxes, MUST use rdf:text as the
datatype for internationalized strings>

=================

"Issue 2: The treatment of xs:string is at odds with the current RDF
specifications."

I agree that in RDF the equivalence of "xyz" and "xyz"^^xs:string is
semantically, but syntactical. Thus, the abbreviation suggested in the
rdf:text spec should not imply that it introduces this change to the
RDF syntax spec. In stead, in addition to your suggestions, we can add
a note in 3.2 saying that

<Note: the abbreviation of a literal of datatype xs:string is a
consequence of the semantic equivalence of the abbreviated and
original forms of the literal, as described by the RDF semantics [RDF
Semantics]. >

Please let me know if the suggested changes sufficiently address your
concerns. I'm happy to further exchange ideas with you, and thank
again for your constructive comments.

[1] http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0001.html
[2] http://www.w3.org/TR/2008/WD-rdf-text-20081202/
[3] http://lists.w3.org/Archives/Public/public-rdf-text/2008OctDec/0028.html

-- 
Jie
http://www.cs.rpi.edu/~baojie
Received on Wednesday, 14 January 2009 17:22:36 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 14 January 2009 17:22:37 GMT