- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Thu, 15 May 2003 19:09:05 -0400
- To: webont <www-webont-wg@w3.org>
Guus and I have been sorting through the comments looking for those
where the WG may have to be in the critical path. We've identified
the ones below as most likely to either raise or reopen an issue. We
will be sending individual messages asking various editors or other
WG members to "volunteer" to write responses (to submit back to the
WG - not to the public-list without an okay first) - the below is to
let everyone know what the list is and to solicit comments on those
you feel strongly about. There are many other comments not on this
list, and we hope the editors will keep working on those in the way
you've been doing so far -- we've made a dent, but there's a long way
to go (*sigh*) - some of these have already been assigned -- in that
case they say ASSIGNED: and to whom...
=======================
General LC comments
overview 13 May
----------
RDFCore: Comments on OWL Reference - owl:class not needed
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0004.html
#owlref-rdfcore-owl-class-denotation
It has been suggested to
RDFCore that owl:Class is not needed. RDFCore requests the
creation of test cases to clearly illustrate the differences
between owl:Class and rdfs:Class.
ISSUE OPENED: NOT YET ASSIGNED (action Hayes)
------------
RDFCore: Comments on OWL Reference - more readable RDF mapping
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0053.html
#owlref-rdfcore-relationship-to-RDF
RDFCore requests that the specifications be amended to include a
description of necessary conditions for a RDF document to be in
OWL DL and OWL Lite. This description should be as accurate as
possible consistent with a goal of it being comprehensible to a
majority of the community.
-------------
RDFCore: NP completeness of owl/RDF mapping
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0052.html
#owlsas-rdfcore-np-complete RDFCore notes the a consequence of the
rules for owl:equivalentClass is that distinguishing OWL DL from OWL
Full has complexity NP complete and suggests WEBONT investigate
whether this complexity can be reduced.
ASSIGNED: PETER P-S
-------------
RDFCore: B-node issues
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0052.html
#owlsas-rdfcore-bnodes-restrictions
[..] we request, that in Owl DL and Owl lite:
a) that a b-node representing an individual may be the object of
more than one triple
b) that cycles of b-nodes representing individuals be allowed.
---------------
Varant: OWL and Published Subjects
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0013.html
[opportunities, no real issues/comments]
ASSIGNED HENDLER
--------------
McGregor: Non-global Keys
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0019.html
OWL ought to include a syntax for defining non-global keys. For
example, suppose the classes Employee and EmployeeHistory both share
the attribute hasSSN. One would like to be able to assert that
'hasSSN' is a key for instances of Employee, but not for instances
of EmpoyeeHistory. InverseFunctionalProperty does not permit this.
ASSIGNED HENDLER/CONNOLLY
--------
Reynolds: OWL comment - language subsets and complexity
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0045.html
We wish to register a comment on the implementation complexity of
the selected subsets of OWL - Lite and DL - based on our
implementation experience with Jena.
One means to simplify OWL/Lite would be to restrict class
definitions to only be "partial". Our concern is that this would go
too far - there is value in having complete definitions in order to
support classification of individuals based on their properties. We
wonder if a constraint of the form "each classId may only
participate in a single axiom of the form Class(classID complete
...)" would remove this source of complexity. We ask those with
greater knowledge of this field to explore whether an approach along
these lines would enable OWL/Lite to better live up to its name.
ASSIGNED HENDLER
-------------
Merry: OWL Comment: have long CR period for OWL, or move owl:oneOf, owl: have
Value to OWL Full
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0046.html
An alternative, would be to redefine OWL DL downwards, excluding
owl:oneOf and owl:hasValue, which would then be subject to the
health warnings of OWL Full - i.e. use of these constructs means
that your ontology is likely to be outside the limits of practical
reasoning. Such a redefinition of OWL DL, could sensibly accompany a
redefinition of OWL Lite to exclude complete class definitions.
ASSIGNED HENDLER
-----------
OWL comment - blank nodes in OWL DL
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0048.html
It is not clear why OWL DL has not permitted, for example, an
unnamed individual to be the object of more than one triple, or an
unnamed individual to be the object of a triple of which it is the
subject. Please either relax this constraint or offer a rationale.
-----------------
Beckett: OWL S&AS comment - owl:imports
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0056.html
See also Use case raised by Golbeck
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0068.html
A semantic import mechanism for the RDF-based languages looks
potentially useful and in considering if and how to implement it,
there are some problems.
Firstly it seems that owl:imports potentially will import the entire
semantic web of OWL Ontologies. Have you considered the security
and denial-of-service implications of this mechanism?
Secondly, is not clear at what stage that this (Imports Closure
http://www.w3.org/TR/2003/WD-owl-semantics-20030331/rdfs.html#5.3 )
should be done. In an example where you have some RDF/XML that will
map to RDF triples describing an OWL ontology, what are the steps
that you expect to happen?
use case: NCI cancer ontology - wants to break into smaller pieces, but
import rebuilds the whole thing.
---------------------
Beckett: OWL Reference comment - RDF Schema for OWL
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0082.html
> Appendix B is not normative.
So that means there is no normative description in machine readable
form of the OWL vocabulary, in OWL, as written down in RDF/XML. Is
all the OWL vocabulary expected to be built-in application
knowledge? What is the purpose of this section? It would benefit
from an explanation.
ASSIGNED GUUS S
----------------------
Beckett: OWL S&AS: Translation to RDF Graphs
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0059.html
[only S&AS?!]
This transformation table gives the mapping from OWL's abstract
syntax to RDF triples which means that if you have an OWL ontology
in the abstract syntax you can write it in OWL's transfer syntax -
RDF triples.
It is however more difficult to see how to go from RDF triples to
OWL's abstract syntax. As a semantic web technology, OWL builds on
RDF triples (and RDF on XML for syntax, URIs etc.) and this form of
presentation makes it harder to see how to start with RDF and gain
from OWL vocabulary.
----------------------
wwmm: AllDisjoint
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0076.html
see also: support from Vatant and McCullough
Alford: AllSame
http://lists.w3.org/Archives/Public/public-webont-comments/
2003May/0070.html see also: Use case raised by biologists
(reported by Hendler)
http://lists.w3.org/Archives/Public/www-webont-wg/2003May/ 0206.html
Since there is an owl:AllDifferent, why is there not an
owl:AllDisjoint? It means that all class disjoint with each
other.
use case: biological taxonoma with 100s of disjoint classes
at some levels. Note this is NOT a disjoint union, just a
large set of disjoints.
ASSIGNED HENDLER
-------------
Laskey: General issues
http://lists.w3.org/Archives/Public/public-webont-comments/2003May/0071.html
I have been thinking about the OWL Last Call drafts for some
time and I have been troubled by a general feel of unease.
While the use cases provide a broad range of interesting and
useful scenarios, my general feeling is that OWL as
presented will not be an effective means to accomplish these
ends. I would be more comfortable if I could point to
specific shortcomings that I could suggest be corrected
(such as the n^2 problem with disjoint classes - why not
have a mutuallyDisjoint construct that is applicable to a
list of arguments?), but my issues go deeper than this. In
discussions with others (including some outside SAIC), I
have encountered a pervasive feeling that OWL might be
interesting but will not have significant impact on real
problems. Any examples in the drafts that go beyond the
trivial are complicated and tedious, and it is unlikely that
anyone beyond a diehard would have the motivation to do any
significant ontology capture in this format.
ASSIGNED HENDLER
Received on Thursday, 15 May 2003 19:09:10 UTC