I hope to submit a more formal position paper but just so you have something in a timely manner, i am submitting this now.

Semantic Web Rule Languages and Explanation
Deborah L. McGuinness

The semantic web is gaining traction and moving beyond the research world into the domains of business.  With this expansion, concerns such as expressivity for business applications and understandability and trust of answers become more important.  In previous work, we have considered issues related to rule language constructs for description logics ([CLASSIC, NeoCLASSIC, BIM96, ...), their usability (MP98, MARSTC94, MRI95,... ), and their explainability (McG96, MB95, BFHMP99, ..). More recently we have participated in the Joint Committee in producing the Semantic Web Rule Language (SWRL http://www.w3.org/Submission/2004/03/).  Simultaneously, we have developed an explanation infrastructure for web applications called InferenceWeb (MP05, http://iw.stanford.edu).  With Inference Web, and its proof interchange language called PML (PMF05), we can provide the necessary infrastructure and services to enable interoperable proofs and proof fragments that can be used to generate explanations from web applications.
Our interest in this workshop has two primary themes including discussing rule language use case issues leading to expressivity issues and rule language design for explanation and interoperation

[BFHMP99] Alex Borgida, Enrico Franconi, Ian Horrocks, Deborah L. McGuinness, and Peter F. Patel-Schneider. ``Explaining ALC subsumption'' Proceedings of the International Workshop on Description Logics - DL-99, pp 33-36, Linköping, Sweden, July 1999.

[BIM96] Alex Borgida, Charles Isbell, and Deborah L. McGuinness, ``Reasoning with Black Boxes: Handling Test Concepts in CLASSIC.'' In Proceedings of International Workshop on Description Logics, Cambridge, Mass., November, 1996

[McG96]  Deborah L. McGuinness. ``Explaining Reasoning in Description Logics''. Ph.D. Thesis, Rutgers University, 1996. Technical Report LCSR-TR-277. abstract and available from Rutgers Deparment of Computer Science Technical Report Series,.

[MARSTCC94]  Deborah L. McGuinness, Merryll K. Abrahams, Lori Alperin Resnick, Peter F. Patel-Schneider, Rich Thomason, Violetta Cavalli-Sforza and Cristina Conati. ``CLASSIC Knowledge Representation System Tutorial.'' Artificial Intelligence Principles Research Department, AT&T Labs Research, 1994. Available from: http://www.bell-labs.com/project/classic/papers/ClassTut/ClassTut.html.

[MB95]  Deborah L. McGuinness and Alex Borgida . ``Explaining Subsumption in Description Logics.'' In Proceedings of the 14th International Joint Conference on Artificial Intelligence, Montreal, Canada, August, 1995. abstract

[MP98] Deborah L. McGuinness and Peter F. Patel-Schneider. ``Usability Issues in Knowledge Representation Systems''. In Proceedings of the Fifteenth National Conference on Artificial Intelligence, Madison, Wisconsin, July, 1998. This is an updated version of ``Usability Issues in Description Logic Systems'' published in Proceedings of International Workshop on Description Logics, Gif sur Yvette, (Paris), France, September, 1997. abstract postscript version

[MP05] Deborah L. McGuinness and Paulo Pinheiro da Silva. Explaining Answers from the Semantic Web: The Inference Web Approach. Web Semantics: Science, Services and Agents on the World Wide Web Special issue: International Semantic Web Conference 2003 - Edited by K.Sycara and J.Mylopoulis. Volume 1, Issue 4. http://www.websemanticsjournal.org/ps/pub/2004-22

[MRI95] Deborah L. McGuinness, Lori Alperin Resnick, and Charles Isbell. ``Description Logic in Practice: A CLASSIC: Application.'' In Proceedings of the 14th International Joint Conference on Artificial Intelligence, Montreal, Canada, August, 1995. The published version is available. An extended version of this with examples is available

[CLASSIC]  Lori Alperin Resnick, Alex Borgida, Ronald J. Brachman, Deborah L. McGuinness, and Peter F. Patel-Schneider. ``CLASSIC Description and Reference Manual for the COMMON LISP Implementation.'' AT&T Bell Laboratories,
[NeoCLASSIC] Lori Alperin Resnick, Peter F. Patel-Schneider, Deborah L. McGuinness, Elia Weixelbaum, Merryll K. Abrahams, Alex Borgida, Ron Brachman, Charles L. Isbell, and Kevin C. Zalondek. ``NeoClassic User's Guide: Version 0.7'' Artificial Intelligence Principles Research Department, AT&T Labs Research, 1996. 
-- 
 Deborah L. McGuinness 
 Co-Director Knowledge Systems Laboratory 
 Gates Computer Science Building, 2A Room 241 
 Stanford University, Stanford, CA 94305-9020 
 email: dlm@ksl.stanford.edu
 URL: http://ksl.stanford.edu/people/dlm
 (voice) 650 723 9770    (stanford fax) 650 725 5850