- From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Date: Sun, 15 Mar 2009 19:31:28 +0000
- To: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Cc: public-owl-wg@w3.org
Ship it! On 12 Mar 2009, at 00:32, Peter F. Patel-Schneider wrote: > [Draft Response for LC Comment 21] JDB2 > > Dear Jos, > > Thank you for your message > <http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/ > 0024.html> > 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 changes neither the form nor 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: > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17912&oldid=17717 > Initial diffs for Syntax can be found at: > http://www.w3.org/2007/OWL/wiki/index.php? > title=Syntax&diff=17910&oldid=17665 > > > Structural Specification and Functional Syntax document: > > The discussion of datatype maps in Section 4 of the Specification > document is not a formal one, it concentrates on those parts of > datatype > maps that are needed for the syntax, deferring formal discussion to > Section 2 of the Direct Semantics document. It is thus appropriate > that > Section 4 of the Syntax document does not explicitly call out the > semantic mappings that are part of datatype maps, only alluding to > their > presence. > > The precisionDecimal datatype of XML Schema perhaps could have been > included in OWL 2. However, the definition of equality and order on > precisionDecimal does not appear to be what would be desired in a > representational setting (which would instead be based on viewing > elements of the datatype as ranges of numbers). > > Due to several comments and implementation experience, hexBinary and > base64Binary now have disjoint value spaces, so there is no difference > from XML Schema. This is a change to OWL 2. > > The OWL WG agrees that PNG would be preferable to GIF. However, > GIF is > acceptable to W3C and the figures have been generated using tools that > only produce GIF. > > > Direct Semantics document: > > 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 > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17913&oldid=17912 > > 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 > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17914&oldid=17913 > > Axiom closure is defined in Syntax. A link to the definition has been > added where the term is used. The diffs are > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17915&oldid=17914 > > If the document was being rewritten from scratch, 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 > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17918&oldid=17915 > > 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 > http://www.w3.org/2007/OWL/wiki/index.php? > title=Direct_Semantics&diff=17932&oldid=17923 > > The above changes are all editorial. > > > Profiles document: > > As stated in the document, OWL 2 RL is designed for easy and efficient > implementation using existing forward-chaining rule systems. Adding > owl:Thing or reflexive object properties needs rules that operate over > all individuals, which goes against efficiency, and may not even be > possible in some rule systems. Similarly, most rule systems are > designed for positive ground facts which dictates against allowing > negative property assertions. > > The phrase "General concepts of the language" has been replaced by an > explicit pointer to Section 13.1 of Syntax. This change was done in > two > phases: > http://www.w3.org/2007/OWL/wiki/index.php? > title=Profiles&diff=prev&oldid=19186 > and > http://www.w3.org/2007/OWL/wiki/index.php? > title=Profiles&diff=19552&oldid=19193 > > The non-terminal subObjectPropertyExpressions is used uniformly > throughout the document set, but it really should be > subObjectPropertyExpression. This is only a change to a non- > terminal in > the grammar, which is an editorial change. The diffs are: > http://www.w3.org/2007/OWL/wiki/index.php? > title=Profiles&diff=18708&oldid=18687 > http://www.w3.org/2007/OWL/wiki/index.php? > title=Syntax&diff=18707&oldid=18533 > > The above changes are all editorial. > > > RDF-Based Semantics document: > > As a general note, please be aware that the RDF-Based Semantics is not > yet a Last Call working draft, and it has received considerable > editing > since the last publication in December. > > It is indeed intended to have the same set of datatypes and facets in > the RDF-Based Semantics spec as in the Structural Specification. The > working group agrees that this should be more explicitly stated, since > it does not easily follow from the text in the published working > draft. Therefore, the working group plans to add clarifying text in > the > next published working draft. > > Note that the OWL 2 RDF-Based Semantics aims for full compatibility > with > the semantics defined in the RDF Semantics specification. The > semantics there already provides notions of datatypes and datatype > maps, > and defines certain semantic conditions for them. In particular, as > for > OWL 1 Full, the central definition of an OWL 2 Full interpretation > provided in the RDF-Based Semantics document builds on top of the > definition of a so called "D-interpretation", as defined in the RDF > Semantics specification, and by this the existing definitions of > datatypes and datatype maps from the RDF Semantics specification are > reused. > > Further, since OWL 2 provides for the new concept of datatype facets, > the definition of a datatype, as given in the RDF Semantics > specification, has been extended by the notion of a facet > space. Extending the definition of a datatype is explicitly > permitted by > the RDF Semantics specification (see section 5.1 of [2]). > > Nevertheless, it is true that the different concepts used in the > definition of the extension for facets did not well match the concepts > used in the Direct Semantics specification in the last published > working > draft. This is currently under revision, and the final outcome will be > that the different concepts are compatible with each other in that the > different notions of datatype maps can be easily transformed in each > other. > > Thank you for pointing out the typographical error "an OWL", it > will be > fixed in the next publication. > > The purpose of Section 6 of the RDF Semantics is to show how the two > semantics of OWL 2, the RDF-Based Semantics and the Direct Semantics, > relate to each other. There is corresponding material in the OWL 1 > recommendations. Be informed that at the time of the last > publication, > this section was in a very early and incomplete state. A final and > much > enhanced version of this section is planned for the next publication. > > > Please acknowledge receipt of this email to > <mailto:public-owl-comments@w3.org> (replying to this email should > suffice). In your acknowledgment please let us know whether or not you > are satisfied with the working group's response to your comment. > > Regards, > Peter F. Patel-Schneider > Michael Schneider > on behalf of the W3C OWL Working Group >
Received on Sunday, 15 March 2009 19:32:06 UTC