Additional non-RDF-XML syntax considered harmful

We are positively opposed to introducing the (non-RDF) XML
serialisation. It's entirely up to the WG to adopt a different
structural specification / abstract syntax if that makes it easier to
define the semantics of the language etc, but we can see no good
reason for turning this internal formalisation-tool into a normative
*additional* serialisation syntax.
The merits of the new syntax are justified in terms of debatable
arguments (a preference for either axiomatic or frame-based syntax is a
matter of taste, not fact).
We also don't see how the introduction of
two serialisation syntaxes (RDF-XML and non-RDF-XML) can make life
easier for developers. Arguably the non-RDF-XML syntax is easier to
handle, but it is mandatory for tools to implement the RDF-XML syntax,
so it's just additional burden.
(see conformance statement 2.1 in <http://www.w3.org/TR/owl2-test/>)
Also, introducing the non-RDF-XML syntax breaks upwards compatibility:
Without any modification, many OWL1 tools will be able to parse all of
OWL2 in  the RDF-XML syntax and most likely even make some semantic sense
of it, while the same OWL1 tools will barf at (or at best entirely
ignore) the same OWL2 ontologies when expressed in the non-RDF-XML
syntax.
It is also noticeable that the Features document does not give any
supporting use-cases for the introduction of the new syntax.
Summarising: this will be a burden on tool developers, and will break
compatibility.
Finally, it breaks with the widespread semantic-web practice that
triples are the exchange currency.
In short: we strongly insist that this syntax will be made non-normative
(comparable to the non-RDF-XML syntax for OWL1)

In relation to this previous point, we would find it useful if the
documents would show the triple-serialisation (ie in RDF-XML) of the
various new constructs, similar to the Guide document for OWL1
<http://www.w3.org/TR/owl-guide/>

Frank van Harmelen,
and many members of the Semantic Web Group at the Vrije Universiteit Amsterdam

-- 
Frank.van.Harmelen@cs.vu.nl		http://www.cs.vu.nl/~frankh
Working on the Large Knowledge Collider	http://www.LarKC.eu

Received on Friday, 23 January 2009 23:58:57 UTC