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Re: Review of QRG

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Sun, 03 May 2009 18:45:51 -0400 (EDT)
Message-Id: <20090503.184551.20055529.pfps@research.bell-labs.com>
To: baojie@cs.rpi.edu
Cc: public-owl-wg@w3.org
From: Jie Bao <baojie@cs.rpi.edu>
Subject: Re: Review of QRG
Date: Sun, 3 May 2009 16:25:19 -0400

> Thanks Peter (again)!
> May I ask a few questions before incorporating  your comments?
> On Sun, May 3, 2009 at 2:03 PM, Peter F. Patel-Schneider
> <pfps@research.bell-labs.com> wrote:
>>        Review of QRG
>> I reviewd the version of 3 May 2009.
>> I fixed a number of typographical and grammatical errors.
>> Some of the suggestions require major changes to the document so a
>> re-review will be needed.
>> Data Property Restrictions
>>     individual value -> literal value
>> 4.1: There is no "hook for n-ary datatype" in Data Ranges
> It was listed a new feature in NF&R
> http://www.w3.org/2007/OWL/wiki/New_Features_and_Rationale#F11:_N-ary_Datatypes

That doesn't mean that there is something that needs to be mentioned in
QRG.  The "hook" is the n-ary existential and universals (and some other
stuff that doesn't show up in QRG).

>> 4.1: Annotation of objects was in OWL 1
>> 4.1: Annotation of annotations is new in OWL 2
>> 4.1: There are many extra built-in datatypes beyond the ones listed.
> The current list is the diff of [1] (OWL 2) to [2] (OWL 1). What are
> other extra built-in datatypes?

The only true built-ins in OWL 1 are xsd;integer and xsd:string.  all
others were optional, and only lightly implemented (if at all).

> [1] http://www.w3.org/2007/OWL/wiki/Syntax#Datatype_Maps
> [2] http://www.w3.org/TR/owl-semantics/syntax.html
>> 2.4: datatype definitions are a kind of axiom
>> 3.1: xsd:dateTime allows the absence of time zone offset
>>     xsd:dateTimeStamp requires time zone offset
>> 2.3: anonymous individuals are written _:a
>> 2.8: The section on annotations has several errors:
>>     - there are annotation assertions
>>       - which can be on any IRI or anonymous individual
>>       - which have value any IRI, anonymous individual, or literal
> do you mean this is wrong, or it should be the case? (actually it is
> it the current writing)

The "i.e." clause in QRG is incorrect and should be removed.

>>     - there are annotations on axioms
>>       - if the axiom has a main blank node
>>          then the annotation triple is on that blank node
>>       - if the axiom generates one or more main triples
>>          then four triples sharing a blank node are added for each main
>>          triple
>>           the annotation generates a triple on each blank node
>>     - there are annotations on annotations
>>       - four triples sharing a blank node are added for the annotation
>>        the new annotation triple is on this blank node
> It seems the current writing is very close to your suggestion, except
> that an axiom can have only one main triple, and the multiple main
> triple case is covered with Note 3.

You allow ontologies in Section 2.8, which is not correct.  Ontology
annotations should be handled uniformaly in Section 2.9.  The above
organization is correct and, I believe, easier to understand.

>> 2.9: The functional syntax for the three annotation properties is wrong.
>> 2.9: The three annotation properties here should be added to the list of
>>     annotation properties in 2.8
> that is the part confuses me (maybe many other users as well). In
> Syntax, they are defined as annotation properties. In RDF semantics,
> then they are introduced as "Ontology Properties" (which is a
> completely new concept w.r.t. Syntax).
> In syntax, they are again mentioned in " Ontology Annotations" with
> notice "The usage of these annotation properties on entities other
> than ontologies is discouraged. "

> It looks a difference between the Syntax and the RDF Semantics. If the
> QRG is a guide to OWL 2 in general (not only OWL DL), then we might
> need to introduce "Ontology Properties".

Syntax is supposed to cover essentially all of OWL 2, and should be
considered the target for QRG.

My suggestion is that in QRG to just make them all be annotation
properties and ignore the "discouragement".

>> 2.0: There are no links to NF&R in the first column.
>> I suggest that the notation situation be cleaned up as follows:
>> - rename Section 1 to  Names, Prefixes, and Notation
>>  Names in OWL 2 are IRIs, often written in a shorthand PF:LCL, where PF
>>  refers to an IRI forming the first part of the name and LCL is the
>>  remainder of the name.  Throughout this document U is any IRI, CN is a
>>  class name, DN is a datatype name, PN is an object property name, RN
>>  is a data property name, AN is an annotation property name, aN is an
>>  individual name, and ON is an ontology name.
>>  OWL 2 individuals can also be globally anonymous, written as _:a where
>>  a is the local identifier for the individual.
>>  Throughout the document C is a class expression, D is a data range, P
>>  is an object property expression, R is a data property expression, a
>>  is an individual, v is a literal, n is a ....
>>  In the RDF syntax, _:x is a blank node and (a1...an) is an RDF list.
>>  All of the previous can have subscripts.
>> - remove the paragraph on notation from Section 2.0
>> - make the appropriate changes throughout the rest of the document
>> 2.1: n-ary Data Ranges do not need to be in this document
> You mean "Restrictions Using n-ary Data Range"? - but it is in the
> Syntax. Why _only_ exclude this construct?

Because you can't do anything useful with it without using the n-ary

>> 2.8: The section on deprecation is not needed and should at least be
>>     moved to an appendix.
> If owl:DeprecatedClass and owl:DeprecatedProperty are not deprecated
> (I think it have been decided a year ago), why document them as
> second-class citizen?

Because they are not generated from any functional syntax.

>> 2.4: The comment that datatypes have arity one is not needed.
>> 3.2: The introductory paragraphs are not needed.  For the second, just
>>     use the same terminology in 3.1 and 3.2.
>> 3.2: The explanation column is not needed.
>> 3.2: "whose value is a" -> "as a"
>> 4.1: this can be drastically shortened by not using lists
>> 4.1: many of the items in the list can be shortened
>>     - remove "(self restriction)"
>>     - remove "restriction" where it is implied
>>     - remove "binary and pairwise"
>> 4.1: All facets are new to OWL 2, so just say so, don't list them.
> Again, I really appreciate your help.
> Jie

Received on Sunday, 3 May 2009 22:45:36 UTC

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