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Reference document: a review

From: <herman.ter.horst@philips.com>
Date: Fri, 20 Dec 2002 09:58:22 +0100
To: mdean@bbn.com, www-webont-wg@w3.org
Message-ID: <OF8F37C5D5.AF14257C-ON41256C92.00347CD7-C1256C95.003179F8@diamond.philips.com>
Below I include comments about the Reference document, version of 19 
December.

In addition to several small, local corrections, I have one suggestion for 
extension, which I
give first.
The purpose of the document is "to serve as a reference guide for users of 
the OWL language".
I believe that this purpose could be much more completely met.
What is now in the document is very useful, but the document includes 
syntax descriptions/examples 
only in a very incomplete way.

The document gives syntax examples in several sections: headers, 
enumerations,
 instances, Boolean combinations (plus a few other syntactic notes in 
Appendix B).
However, the document does not give syntax descriptions/examples for the 
four other, 
very important, sections:
class elements, class expressions, property restrictions, property 
elements.
So the document cannot be used as a reference for the syntax of these 
aspects
of the language.

The document says this about syntax, in section 1:
"The normative reference on the precise syntax of the language constructs 
is the 
machine readable RDF Schema definition of OWL, also included as Appendix 
C."
However, this appendix is not advisable for many humans who quickly want 
to see 
how a certain piece of syntax goes.

Where can an OWL user go in the official documents for more complete 
OWL/RDF/XML 
syntax examples, in a human-readable way? 
The Feature Description has in its purpose, naturally, not to give syntax
examples.  The Guide document contains more examples, but is very long, 
and therefore 
not ideal to use as a reference. Moreover, the Guide has not the purpose 
to be a reference.

I believe that the reference document would become immensely more useful 
when it adds
a few syntactic examples for the mentioned sections:
class elements, class expressions, property restrictions, property 
elements.
These examples do not need to be complete, but should convey the main idea
of the syntax, so that with the precise names of the language elements 
already included,
the document becomes more complete (even more or less complete) as a 
reference. 
For example, if an example with allValuesFrom is given, then 
someValuesFrom does not need
to be given.
It would need to cost only very few pages extra in total (it seems to be 
doable in less than 2), 
keeping the document to a small, attractive size.

==

And now the corrections:

-  " an allValuesFrom element (which contains a class expression)"
add here between the brackets: or a datatype reference.
Note that ".. or datatype" is already contained in the next, explanatory, 
sentence.
Compare also someValuesFrom elements two bullets further on, where this is 
also included.

-  a typo at allValuesFrom: the class of objects x (s added to object)

-  domain elements: 11th line: in the middle of a sentence: class instead 
of Class

-  owl:inverseOf elements: this should be iff instead of if: so the 
sentence could be:
More formally: the pair (x,y) is an instance of P if and only if the pair 
(y,x)
is an instance of the named property.

Herman ter Horst
Philips Research
Received on Friday, 20 December 2002 04:01:07 GMT

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