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Please see OWL Implementations for a more up-to-date OWL implementation report. [This note added 2003-09-17, no other modifications since 2003-07-30]

Request for Candidate Recommendation Status and preliminary Implementation Report

$Revision: 1.43 $ of $Date: 2003/09/17 03:02:29 $
Dan Connolly and Jim Hendler

Dear W3C Director,


the Web Ontology Working group have decided (24 July) to request that you advance this specification to W3C Candidate Recommendation and call for implementation.

Titles, Abstracts, and Proposed Status

Status of This Document (proposed)

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than "work in progress".

This 18 Aug 2003 (PENDING CONFIRMATION) draft, along with the other working drafts for OWL, are a Candidate Recommendation; it been widely reviewed and satisfies the Working Group's technical requirements; W3C publishes a Candidate Recommendation to gather implementation experience.

The first release of this document was 4 November 2002 (tune to each part) and the Web Ontology Working Group has made its best effort to address comments received since then, releasing several drafts and resolving a list of issues meanwhile. The design has stabilized, and once the exit criteria below are met, the Working Group intends to advance this specification to Proposed Recommendation.

Patent disclosures relevant to this specification may be found on the Working Group's public patent disclosure page.

Comments on this document should be sent to public-webont-comments@w3.org, a mailing list with a public archive. General discussion of related technology is welcome in www-rdf-logic@w3.org (archive).

This document has been produced as part of the W3C Semantic Web Activity (Activity Statement) following the procedures set out for the W3C Process. The document has been written by the Web Ontology Working Group. The goals of the Web Ontology working group are discussed in the Web Ontology Working Group charter.

Summary of Review

Starting in November 2001, review followed the scope section of the Working Group charter:

The Working Group shall start by evaluating the technical solutions proposed in the DAML+OIL draft. If in this process the Working Group finds solutions that are agreed to be improvements over solutions suggested by DAML+OIL, those improved solutions should be used.

The first Working Drafts were released in July 2002 for review by the community, including groups with identified dependencies.

About 50 issues were identified by the Working Group during the review.

Dependencies were discharged as follows:

The Working Group responded to comments on a best-effort basis throughout the review, and formally addressed all of the last call-comments. We received 74 comments in all. Of these we have answered and been acknowledged on 63 messages. For 11 more we have not received acknowledgements yet - on 9 of these we agreed or mostly agreed with the comment raiser and made edits to our documents in response. One comment has not been answered to the commentor's satisfaction, and we address this below. See disposition and summary of comments and OWL-generated view for a detailed list.

We achieved consensus on all but two issues:

5.6 daml:imports as magic syntax

This issue, regarding how the imports feature of DAML+OIL fits with the rest of OWL, was raised May 2002 and discussed at length before being resolved in November 2002. Dissenters Hendler/MIND, Connolly/W3C and Welty/IBM argued that the WG should postpone the issue, but the proposal by Hefflin to specify a sufficient level of detail for how imports works gained considerably more support, and no other proposals have become available. Last call comments on this feature were addressed to the satisfaction of the commentors with minor editorial changes to the specifications. A Feb 2003 report from the Jena/HP development team reports their satisfaction with supporting the feature.

Since this design seems to be specified to the satisfaction of a critical mass of the community; we ask that The Director confirm the WG decision despite the outstanding dissent.

5.26-OWL DL Syntax)

Beckett/ILRT commented on section 4.1 Translation to RDF Graphs in the OWL Semantic and Abstract Syntax, arguing that "Providing half of a complex mapping between an abstract syntax to/from a concrete syntax seems insufficient to me." The working group discussed mappings that went both ways (e.g. Carroll 21 Jan) as these two-way mappings involved substantive as well as editorial changes, did not work out the remaining design details before the 31 March Last Call.

The Working Group did accept an exit criterion to verify that the design is implementable by exhibiting two OWL syntax checkers. In light of this criterion and Beckett's comment that "Maybe you do have multiple interoperable implementations of the mapping from OWL's concrete syntax (RDF triples) to OWL's abstract syntax and I am just unaware of them. If that is the case, then I would be more satisfied." We ask the Director to confirm the WG decision despite this dissent.

Feature at risk

Per Section 7.4.3 of the Process Document, the Web Ontology Working Group would like to declare that one feature of our current technical reports are "at risk." In particular, the semantics of OWL DL appear to be simpler to prove if certain restrictions are made on the use of bnodes in the RDF graphs that are allowed in OWL DL. However, the restrictions may be difficult to implement. The Working Group has therefore decided to place these restrictions on bnodes "at risk" and call for implementation experience to determine the implementability of these restrictions. The details of the document changes below present the details of effected tests and documents.

Implementation Experience

The following implementation experience leads us to believe that once the exit criteria below are met, we will have sufficient implementation experience to validate the design and merit widespread deployment.

Candidate Recommendation Exit Criteria

Details of the feature at risk

The following tests would change from being OWL Full (in)consistency tests of OWL Full files, to being OWL Lite and OWL Full (in)consistency tests of OWL Lite files:

The following tests would change from being OWL Full (in)consistency tests of OWL Full files, to being OWL DL and OWL Full (in)consistency tests of OWL DL files:

The following similar tests would be unchanged (in OWL Lite or OWL DL):

The following similar tests would be unchanged (in OWL Full):