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

partial response for LC comment 21 JDB2

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 19 Feb 2009 16:26:58 -0500 (EST)
Message-Id: <20090219.162658.14105294.pfps@research.bell-labs.com>
To: public-owl-wg@w3.org
I have handled some of the comments in LC comment 21.  The other
comments are for other documents.  Editors of these documents are
welcome to augment the response.  I may also be able to make some of the


[Draft Response for LC Comment 21, partial]

Dear Jos,

Thank you for your message
on the OWL 2 Web Ontology Language last call drafts.

Anchors have been added in many places, feel free to ask for more, as
adding anchors does not change the form or the meaning of the documents.
The general form of the anchors are def_<term_with_underscores>, but
this was not feasible in all cases.   The documents provide anchors for
each section which can also be used in other documents.

Diffs are not provided here for all changes, as the addition of anchors
may have been interspersed with other work on the documents. 

Initial diffs for Direct Semantics can be found at:
Initial diffs for Syntax can be found at:

Full linking from the Direct Semantics is a major task, which would, for
example, include linking syntax.  Links have been added in the
Vocabulary section.
The diffs are

The definition for datatype maps in Direct Semantics extends datatype
maps from RDF Semantics, in particular for facets.  

The wording "satisfies appropriate conditions listed in the following
sections" in Section 2.3 has been changed to "satisfies the condition in
the tables below for the axiom".
The diffs are

Axiom closure is defined in Syntax.  A link to the definition has been
added where the term is used.
The diffs are

If the document was being rewritten from the start, the subsections of
section 2.3 might not be needed, but they seem to be innocuous and will
stay for now.

The definition of axiom closure from Syntax includes "renaming apart" so
the parentheses in 2.3.6 are appropriate.

Section 2.5 now includes a standard definition for variables and the
definition of Boolean Query Answering notes that quantification needs to
be considered.  The diffs are 

In Section 3 "is is" has been replaced by "is".  No diffs are available
for this interesting change.

The second edition of the DL handbook is now referenced.  Again no diffs
are available for this useful change.

I is uniformly used as a signal for an interpretation, instead of
sometimes Int and sometimes I.  The diffs are 

The above changes are all editorial.


Remaining comments:

An overall editorial comment/request:
- Could you create HTML anchors for all definitions in the documents?  I
would like to be able to link directly to definitions of, e.g., datatype
maps and vocabularies.

=== Syntax ====

- the definition of datatypes in section 4 lacks the lexical-to-value
and facet-to-value mappings [these are clearly part of the datatype]
- for the datatypes you rely on XML Schema 1.1 datatypes, and you seem
to have included most of them that make sense.  But you have not
included precisionDecimal.  Is there a rationale for that?
- the difference in your definition of the value spaces of hexBinary and
base64Binary (i.e., non-disjoint) and the definition of XML schema
(i.e., disjoint) should be pointed out in the document, as you did for
the numeric types
- I strongly suggest you use the PNG format for the images in the
document, rather than GIF.  I suspect this is even W3C policy.

=== Profiles ===

- in OWL 2 RL I do not understand why the following features are not
included -- they are easily implemented the rules:
* ReflexiveObjectProperty
* owl:Thing
* negative class and property assertions
- in section 6, I could not find the "productions defining the general
concepts of the language". could you include a direct link?
- section 6.1 and 6.3: "subObjectPropertyExpressions" =>

=== RDF-Based Semantics ===

- if there are differences between the datatypes and facets in tables
2.2 and 2.3, on the one hand, and the datatypes and facets in that
syntax specification, these should be mentioned.  If there are no
differences, this fact should be mentioned as well.
- in my opinion, this document should use exactly the same definition of
datatype map as the direct semantics specification.
- above definition 4.2: "a OWL" => "an OWL"
- I do not understand the purpose of section 6.  There are no notions of
consistency or entailment that could be implemented, so I don't see how
anyone could exploit theorem 6.1.

Jos de Bruijn            debruijn@inf.unibz.it
Received on Thursday, 19 February 2009 21:27:13 UTC

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