All research papers.

Publications on Database Theory and Systems:

Articles and Reports on Database Theory and Systems:

Hegner, Stephen J., and Ruth A. Maulucci, Set-theoretic foundations of data-structure representation, Information Systems, 3 (1978), pp. 193--201.

Hegner, Stephen J., User view updates in relational database systems -- a semantic approach, Proceedings of the 1979 Conference on Information Sciences and Systems, 28-30 March, Johns Hopkins University, pp. 408-413. PDF

Hegner, Stephen J., Algebraic aspects of relational database decomposition, Proceedings of the Second ACM SIGACT-SIGMOD Symposium on Principles of Database Systems, 21-23 March 1983, Atlanta, pp. 400-413. PDF

Hegner, Stephen J., Canonical view update support through Boolean algebras of components, Proceedings of the Third ACM SIGACT-SIGMOD Symposium on Principles of Database Systems, 2-4 April 1984, Waterloo, Canada, pp. 163-172. PDF

Hegner, Stephen J., Specification and implementation of programs for updating incomplete information databases, Proceedings of the Sixth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 22-25 March 1987, San Diego, pp. 146-158. PDF

Hegner, Stephen J., Decomposition of relational schemata into components defined by both projection and restriction, Proceedings of the Seventh ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 21-23 March 1988, Austin, Texas, pp. 174-183. PDF

Hegner, Stephen J., Some open problems on view axiomatization, Bulletin of the EATCS, No. 40, February 1990, pp. 496-498. PDF

Hegner, Stephen J., Foundations of canonical update support for closed database views, ICDT'90, Third International Conference on Database Theory, Paris, France, December 1990, Springer-Verlag Lecture Notes in Computer Science, Volume 470, 1990, pp. 422-436. PDF
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Hegner, Stephen J., Pairwise-definable subdirect decompositions of general database schemata, Proceedings of the Third Symposium on Mathematical Fundamentals of Database and Knowledge Base Systems, 5-9 May 1991, Rostock, Germany, Springer-Verlag Lecture Notes in Computer Science, Volume 495, 1991, pp. 243-257. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Characterization of desirable properties of general database decompositions, Annals of Mathematics and Artificial Intelligence, 7 (1993), pp. 129-195. Penultimate version PDF
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Hegner, Stephen J., Unique complements and decompositions of database schemata, Journal of Computer and System Sciences, 48 (1994), pp. 9-57. Penultimate version PDF

Hegner, Stephen J., Uniqueness of update strategies for database views, Foundations of Information and Knowledge Systems, Second International Symposium, FoIKS 2002, Salzau Castle, Germany, February 20-23 2002, Proceedings, Thomas Eiter and Klaus-Dieter Schewe, editors. Springer-Verlag Lecture Notes in Computer Science, Vol. 2284, 2002, pp. 230-249. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., An order-based theory of updates for closed database views, Annals of Mathematics and Artificial Intelligence, 40 (2004), pp. 63-125. ] Penultimate version PDF
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Hegner, Stephen J., A simple counterexample to the finite axiomatizability of relational views, unpublished note, 2003. PDF

Hegner, Stephen J., The relative complexity of updates for a class of database views, Foundations of Information and Knowledge Systems, Third International Symposium, FoIKS 2004, Wilhelminenburg [sic] Castle, Austria, February 17-20 2004, Proceedings, Dietmar Seipel and José María Turull Torres, editors. Springer-Verlag Lecture Notes in Computer Science, Volume 2974, 2004, pp. 155-175. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., The complexity of embedded axiomatization for a class of closed database views, Annals of Mathematics and Artificial Intelligence 46 (2006), pp. 38-97. PDF
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Hegner, Stephen J. and Peggy Schmidt, Update support for database views via cooperation, Advances in Databases and Information Systems, 11th East European Conference, ADBIS 2007, Varna, Bulgaria, September 29 - October 3, 2007, Proceedings, Yannis Ioannidis, Boris Novikov, and Boris Rachev, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 4690, 2007, pp. 98-113. Corrected version PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., A model of database components and their interconnection based upon communicating views, Information Modelling and Knowledge Systems XIX, Hannu Jakkola, Yashui Kiyoki, and Takehiro Tokuda, editors, IOS Press, 2008, pp. 79-100. Penultimate version PDF
[© IOS Press holds the legal copyright to the final version of this work, which is available via the following URL .]

Hegner, Stephen J., Information-optimal reflections of view updates on relational database schemata, Foundations of Information and Knowledge Systems, Fifth International Symposium, FoIKS 2008, Pisa, Italy, February 11-15, 2008, Proceedings, Sven Hartmann and Gabriele Kern-Isberner, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 4932, 2008, pp. 112-131. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Semantic bijectivity and the uniqueness of constant-complement updates in the relatiional context, SDKB 2008, International Workshop on Semantics in Data and Knowledge Bases, Nantes, France, March 29, 2008, Proceedings, Klaus-Dieter Schewe and Bernhard Thalheim, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 4925, 2008, pp. 172-191. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Optimal reflection of bidirectional view updates using information-based distance measures, Proceedings of the International Workshop on Logic in Databases (LID 2009), Roskilde University, Denmark, October 29, 2009, Leopoldo Bertossi and Henning Christiansen, editors, pp. 57-70. PDF Link to the entire proceedings.

Hegner, Stephen J., Internal representation of database views, Journal of Universal Computer Science. 16 (2010), pp. 2956-2985 Link to the online journal (open access) with PS.gz and PDF files

Hegner, Stephen J., A simple model of negotiation for cooperative updates on database schema components, Information Modelling and Knowledge Systems XXII, Anneli Heimbürger, Yasuni Kiyoki, Takehiro Tokuda, Hannu Jakkola, and Naofumi Yoshida, editors, IOS Press, 2011, pp. 154-173. Penultimate version PDF
[© IOS Press holds the legal copyright to the final version of this work, which is available via the following URL .]

Hegner, Stephen J., Characterization of optimal complements of database views defined by projection, Semantics in Data and Knowledge Bases, 4th International Workshops, SDKB 2010, Bordeaux, France, July 5, 2010, Revised Selected Papers, Klaus-Dieter Schewe and Bernhard Thalheim, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 6384, 2011, pp. 73-95. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., A model of independence and overlap for transactions on database schemata, Advances in Databases and Information Systems, 14th East European Conference, ADBIS 2010, Novi Sad, Serbia, September 20-24, 2010, Proceedings, Barbara Catania, Mirjana Ivanovic, and Bernhard Thalheim, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 6295, 2010, pp. 209-223. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Information-based distance measures and the canonical reflection of view updates, Annals of Mathematics and Artificial Intelligence. 63 (2011), pp. 317-355. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Independent update reflections on interdependent database views, Conceptual Modelling and Its Theoretical Foundations - Essays Dedicated to Bernhard Thalheim on the Occasion of His 60th Birthday, Antje Düsterhöft, Meike Klettke, and Klaus-Dieter Schewe, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 7260, 2012, pp. 101-115. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., FD covers and universal complements of simple projections, Foundations of Information and Knowledge Systems, Seventh International Symposium, FoIKS 2012, Kiel, Germany, March 5-9, 2012, Proceedings, Thomas Lukasiewicz and Attila Sali, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 7153, 2012, pp. 184-202. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Invariance properties of the constant-complement view-update strategy, Semantics in Data and Knowledge Bases, 5th International Workshop, SDKB 2011, Zürich, Switzerland, July 3, 2011, Revised Selected Papers, Klaus-Dieter Schewe and Bernhard Thalheim, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 7693, 2013, pp. 118-148. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Automated design of updateable database views: a framework for possible strategies (abstract only), Automated Reasoning on Conceptual Schemas (Dagstuhl Seminar 13211), Schloss Dagstuhl -- Leibniz-Zentrum für Informatik, May 19-24, 2013, Diego Calvanese, Sven Hartmann, and Ernest Teniente, editors, p. 57, Dagstuhl Reports 3(5), pp. 43-77, 2013. PDF Link to the entire report.

Hegner, Stephen J., Guard independence and constraint-preserving snapshot isolation, Foundations of Information and Knowledge Systems, Eighth International Symposium, FoIKS 2014, Bordeaux, France, March 3-7, 2014, Proceedings, Christoph Bierle and Carlo Meghini, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 8367, 2014, pp. 231-250. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Constraint-preserving snapshot isolation, Annals of Mathematics and Artificial Intelligence, 76 (2016), pp. 281-326. PDF (Corrected version 2017-07-15)
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Errata sheet for the journal version: PDF

Hegner, Stephen J. and M. Andrea Rodríguez, Integration integrity for multigranular data, Advances in Databases and Information Systems, 20th East European Conference, ADBIS 2016, Prague, Czech Republic, August 29-31, 2016, Proceedings, Jaroslav Pokorny, Mirjana Ivanovic, Bernhard Thalheim, and Perr Saloun, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 9809, 2016, pp. 226-242. PDF
[© Springer-Verlag holds the legal copyright to this work. The final publication is available at Springer via https://dx.doi.org/10.1007/978-3-319-44039-2_16 .]

Hegner, Stephen J. and M. Andrea Rodríguez, A model for multigranular data and its integrity, Informatica, Lith. Acad. Sci., 28 (2017), pp. 45-78. Link to the online journal (open access) with full PDF

Hegner, Stephen J., Tolerant constraint-preserving snapshot isolation: extended concurrency for interactive transactions, Models: Concepts, Theory, Logic, Reasoning and Semantics, Essays Dedicated to Klaus-Dieter Schewe on the Occasion of his 60th Birthday, Atif Mashkoor, Qing Wang and Bernhard Thalheim, editors. College Publishing, 2018, pp. 122-145. PDF

Hegner, Stephen J. and M. Andrea Rodríguez, Implicit representation of bigraular rules for multigranular data, Database and Expert Systems Applications -- 29th International Conference, DEXA 2018, Regensburg, Germany, September 3-6, 2018, Proceedings, Part I, Sven Hartmann, Hui Ma, Abdelkader Hameurlain, Günther Permul, and Roland R. Wagner, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 11029, 2018, pp. 372-389. PDF
[© Springer-Verlag holds the legal copyright to this work. The final publication is available at Springer via https://doi.org/10.1007/978-3-319-98809-2_23 .]

Hegner, Stephen J., Transaction isolation in mixed-level and mixed-scope settings, Advances in Databases and Information Systems, 23rd European Conference, ADBIS 2019, Bled, Slovenia, September 8-11, 2019, Proceedings, Tatjana Welzer, Johann Eder, Vili Podgorelec, and Aida Kamišalić Latifić, editors, Springer-Verlag Lecture Notes in Computer Science, Volume 11695, 2019, pp. 390-406. PDF (Corrected version July 28, 2019)
[© Springer-Verlag holds the legal copyright to this work. The final publication is available at Springer via https://doi.org/10.1007/978-3-030-28730-6_24 .]

Conference Proceedings and Journal Special Issues Edited on Database Theory and Systems:

Dix, Jürgen and Stephen J. Hegner, editors, Foundations of Information and Knowledge Systems, Fourth International Symposium, FoIKS 2006, Budapest, Hungary, February 14-17, 2006, Proceedings, Springer-Verlag Lecture Notes in Computer Science, Volume 3861, 2006. SpringerLink
Dix, Jürgen and Stephen J. Hegner, editors, Selected Papers From FoIKS (2006), Annals of Mathematics and Artificial Intelligence, Vol. 50, Nos. 1-2, June 2007. SpringerLink

Publications on Unification, Type Hierarchies, and Computational Linguistics

Papers and Reports on Unification, Type Hierarchies, and Computational Linguistics

Hegner, Stephen J., Horn extended feature structures: fast unification with negation and limited disjunction, Proceedings of the Fifth Conference of the European Chapter of the Association for Computational Linguistics, Berlin, 9--11 April 1991 , Association for Computational Linguistics, 1991, pp. 33-38. [This is a preliminary version of the ideas elaborated in the next report.] PDF

Hegner, Stephen J., Horn clauses and feature-structure logic: principles and unification algorithms, Technical Report No. 1, Language, Logic, and Information Series, Department of Linguistics, University of Oslo, June 1993. PDF

Hegner, Stephen J., Properties of Horn clauses in feature-structure logic, Constraints, Language, and Computation , edited by M. Rosner, C. J. Rupp, and R. Johnson, Academic Press, 1994, pp.111-147. [This is an abbreviated version of Technical Report No. 1 of the Department of Linguistics, University of Oslo, listed above.]

Hegner, Stephen J., Distributivity in incompletely specified type hierarchies: principles and unification algorithms, in Computational Aspects of Constraint-Based Linguistic Description II, DYANA-2, Dynamic Interpretation of Natural Language, ESPRIT Basic Research Project 6852, Deliverable R1.2.B, September 1994, pp. 29-120. Also available as Technical Report No. 4, Language, Logic, and Information Series, Department of Linguistics, University of Oslo, September 1994. PDF

Hegner, Stephen J., A family of decidable feature logics which support HPSG-style set and list constructions, Logical Aspects of Computational Linguistics, First International Conference, LACL'96, Nancy, France, September 1996, Selected Papers, C. Retoré, editor, Springer-Verlag Lecture Notes in Artificial Intelligence, Vol. 1328, 1997, pp. 208-227. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Computational and structural aspects of openly specified type hierarchies, Logical Aspects of Computational Linguistics, Third International Conference, LACL'98, Grenoble, France, December 14-16 1998, Selected Papers, Michael Moortgat, editor. Springer-Verlag Lecture Notes in Artificial Intelligence, Vol. 2014, 2001, pp. 48--69. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., User manual for suqseq-marker, Umeå University, Sweden, July 1999, 31 pp. PDF

Hegner, Stephen J., Characterization of type hierarchies with open specification, Semantics in Databases: Second International Workshop, Dagstuhl Castle, Germany, January 7-12, 2001, Revised Papers, L. Bertossi, G. O. Katuna, K.-D. Schewe, and B. Thalheim, editors, Springer-Verlag Lecture Notes in Computer Science, Vol. 2582, 2003, pp. 100-118. PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Hegner, Stephen J., Generalized Horn constraints and tractable inference on type hierarchies with open specification, unpublished. PS.gz PDF

Publications on Computer Help Systems:

Articles and Reports on Computer Help Systems:

Douglass, Robert J., and Stephen J. Hegner, An expert consultant for the UNIX operating system: bridging the gap between the user and command language semantics, in Proceedings of the Fourth CSCSI/SCEIO Conference, 17-19 May 1982, Saskatoon, pp. 119-127. PDF

Hegner, Stephen J., and Robert J. Douglass, Knowledge base design for an operating system expert consultant, Proceedings of the Fifth CSCSI/SCEIO Conference, 15-17 May 1984, London, Canada, pp. 159-161. PDF

Hegner, Stephen J., Representation of command language behavior for an operating system consultation facility, Proceedings of the Fourth (IEEE) Conference on Artificial Intelligence Applications, 14-18 March 1988, San Diego, pp. 50-55. PDF

Hegner, Stephen J., Plan realization for complex command interaction in the UNIX help domain, Artificial Intelligence Review, 14 (2000), pp. 181-228. Penultimate version PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]

Journal Special Issues Edited on Computer Help Systems:

Hegner, Stephen J., Paul Mc Kevitt, Peter Norvig, and Robert Wilensky, editors, Intelligent Help Systems for UNIX, Part 1: Computational Models and Systems, Artificial Intelligence Review, Vol. 14, Nos. 1-2, 2000. SpringerLink
Hegner, Stephen J., Paul Mc Kevitt, Peter Norvig, and Robert Wilensky, editors, Intelligent Help Systems for UNIX, Part 2: Planning and Knowledge Representation, Artificial Intelligence Review, Vol. 14, No. 3, 2000. SpringerLink
Hegner, Stephen J., Paul Mc Kevitt, Peter Norvig, and Robert Wilensky, editors, Intelligent Help Systems for UNIX, Part 3: Natural Language Dialog, Artificial Intelligence Review, Vol. 14, Nos. 4-5, 2000. SpringerLink

Books Edited on Computer Help Systems:

Hegner, Stephen J., Paul Mc Kevitt, Peter Norvig, and Robert Wilensky, editors, Intelligent Help Systems for UNIX, Kluwer Academic Publishers, 2000. Springer Page
This book consists of the papers of the above three special issues of the journal Artificial Intelligence Review .

Publications on Mathematical System Theory:

Articles and Reports on Mathematical System Theory:

Hegner, Stephen J., Algebraic simplification of interconnected systems, UCID-17760, Lawrence Livermore Laboratory, March 1978. PDF
Hegner, Stephen J., Structured action approach to continuous-time systems, Proceedings of the 1978 Conference on Information Science and Systems, 29-31 March, Johns Hopkins University , pp. 152-157. PDF
Hegner, Stephen J., Duality theory for discrete-time linear systems, Journal of Computer and System Sciences, 17 (1978), pp. 116-143.
Corynen Guy C., Aggarwal, Sudhir, and Hegner, Stephen J., Towards a mathematical theory of modeling, Systems Engineering for Power: Organizational Forms for Large Scale Systems, 30 Sept. - 5 Oct. 1979, Davos, Switzerland .
Hegner, Stephen J., An algebraic approach to continuous-time linear systems defined over Banach spaces, Proceedings of the 1980 Conference on Information Sciences and Systems, 26-28 March, Princeton University, pp. 347-352. PDF
Hegner, Stephen J., Linear decomposable systems in continuous time, SIAM Journal on Mathematical Analysis, 12 (1981), pp. 243-273.
Hegner, Stephen J., Image factorization in relative categories, unpublished, July 1982. PDF
Hegner, Stephen J., Algebraic representation of dynamics and behavior for continuous-time linear systems, Mathematical Systems Theory, 22 (1989), pp. 227-254. Penultimate version: PDF
[© Springer-Verlag holds the legal copyright to this work. The original publication is available at www.springerlink.com via the following URL .]
Hegner, Stephen J., Universal representation of the behavior of linear systems in both discrete and continuous time: a unified overview, CWI Quarterly, 4 (1991), pp. 45-68. Penultimate version: PDF