Jakob Grue Simonsen

Summary

Jakob Grue Simonsen, cand. scient., PhD, MBA
Assistant professor at DIKU.

Research Interests

My primary research theme is the mathematics of computation (how to describe the act of performing computations by man, alien, or machine by mathematics). This includes computing and calculations involving mathematical structures that are intrinsically infinite in nature, but must necessarily be computed using only finite resources.

Note to students: You owe it to yourself to look at the above at least once in your lifetime. Be wary of research parading as "theory with applications" which is more often than not ugly math with no real applications.

A secondary research theme is the practical application of well-established research to down-to-earth problems, e.g. processing of natural language for the web, or development of enterprise resource planning systems.

Note to students: I have plenty of projects in the offering for the above, all with a major dose of development, but only a minor dose of theory.

These days, my primary theme mainly concerns the following:

Publications

In (a reasonable approximation to) reverse chronological order.

International peer-reviewed journals:

[AJ11] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems: Normalising Reduction Strategies".
Logical Methods in Computer Science. To appear.
[AJ10] J.G. Simonsen, "Beta-Shifts, their Languages and Computability".
Theory of Computing Systems. To appear.
[AJ9] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems: Confluence".
Logical Methods in Computer Science 5(4), paper 3, 2009.
published version (open access)
[J8] J.G. Simonsen, "On the Computational Complexity of the Languages of General Symbolic Dynamical Systems and Beta-Shifts".
Theoretical Computer Science 410, p. 4878--4891, 2009.
published version preliminary version
[J7] F. Henglein, K.F. Larsen, C. Stefansen, J.G. Simonsen, "POETS: Process-Oriented Event-Driven Transaction Systems".
Journal of Logic and Algebraic Programming 78(5), p. 381--401, 2009.
published version preliminary version
[J6] J. Andersen, E. Elsborg, F. Henglein, J.G. Simonsen, C. Stefansen, "Compositional Specification of Commercial Contracts".
International Journal on Software Tools for Technology Transfer 8(6), p.485--516, 2006.
published version preliminary version
[J5] J.G. Simonsen "On Local Non-Compactness in Recursive Mathematics"
Mathematical Logic Quarterly 52(4), p. 323--330, 2006.
published version preliminary version
[J4] J.G. Simonsen, "On Modularity in Infinitary Rewriting".
Information and Computation 204(6), p. 957--988, 2006.
published version preliminary version
[J3] J.G. Simonsen "On the Computability of the Topological Entropy of Subshifts"
Discrete Mathematics and Theoretical Computer Science 8, p. 83--96, 2006.
published version (open access).
[J2] J.G. Simonsen, "Specker Sequences Revisited".
Mathematical Logic Quarterly (formerly Zeitschrift fuer Mathematische Logik und Grundlagen der Mathematik). 51(5), p. 532--540, Wiley Interscience, 2005.
preliminary version
[J1] J.G Simonsen, "On Confluence and Residuals in Cauchy Convergent Transfinite Rewriting"
Information Processing Letters 91(4), p.141-146, Elsevier, 2004.
published version preliminary version

International peer-reviewed conferences

[C8] J. Ketema and J.G. Simonsen, "Least Upper Bounds on the Size of Church-Rosser Diagrams in Term Rewriting and Lambda Calculus".
Proceedings of the 10th International Symposium on Functional and Logic Programming (FLOPS '10). To appear.
[C7] S. Hedegaard, S. Houen, J.G. Simonsen, "LAIR: A Language for Automated Semantics-Aware Text Sanitization based on Frame Semantics".
Proceedings of the 3rd IEEE International Conference on Semantic Computing (ICSC '09), p. 47--52. IEEE Computer Society 2009.
published version
[C6] J.G. Simonsen, "The Π ₀²-Completeness of most of the Properties of Rewriting You Care About (and Productivity)".
Proceedings of the 20th International Conference on Rewriting Techniques and Applications (RTA '09). Lecture Notes in Computer Science 5595, p. 535--549. Springer Verlag, 2009.
published version preliminary version
[C5] J. Ketema, J.G. Simonsen, "On Confluence of Infinitary Combinatory Reduction Systems".
Proceedings of the 12th International Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR 2005). Lecture Notes in Artificial Intelligence 3835, p. 199--214, Springer-Verlag, 2005.
published version preliminary version
[C4] J.G. Simonsen, "On Beta-Shifts having Arithmetical Languages".
Proceedings of the 30th International Symposium on Mathematical Foundations of Computer Science (MFCS 2005). Lecture Notes in Computer Science 3618, p. 757--768, Springer-Verlag, 2005.
published version preliminary version
[C3] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems".
Proceedings of the 16th International Conference on Rewriting Techniques and Applications (RTA 2005). Lecture Notes in Computer Science 3467, p. 438--452, Springer-Verlag, 2005.
published version preliminary version
[C2] J. Andersen, E. Elsborg, F. Henglein, J.G. Simonsen, C. Stefansen, "Compositional Specification of Commercial Contracts".
Proceedings of the 1st International Symposium on Leveraging Applications of Formal Methods (ISOLA 2004). University of Cyprus Report TR-2004-6, 103-110. University of Cyprus 2005. (Superseded by [J6]).
preliminary version
[C1] J.G. Simonsen, "On the Modularity of Confluence in Infinitary Term Rewriting".
Proceedings of the 15th International Conference on Rewriting Techniques and Applications (RTA 2004). Lecture Notes in Computer Science 3091, p.185-199, Springer-Verlag, 2004 (Superseded by [J4]).
published version (recommended, requires subscription) preliminary version
Received the RTA 2004 Best Paper Award.

Invited and workshop papers

[W4] L. Hartmann, N.D. Jones, J.G. Simonsen, "Programming in Biomolecular Computation". Nordic Workshop in Programming Theory (NWPT '09).
[W3] M.I. Nielsen, K.F. Larsen, J.G. Simonsen, "Requirements for Logical Models for Value-Added Tax Legislation". Short paper session of the Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR '08).
[W2] L. Hartmann, N.D. Jones, J.G. Simonsen, "Interpretive Overhead and Optimal Specialisation. Or: Life without the Pending List". First Workshop on Metacompuation in Russia (META 2008).
[I1] F. Henglein, K.F. Larsen, C. Stefansen, "Compositional Contract Specification for REA". Invited paper for the First Workshop on Formal Languages and Analysis of Contract-Oriented Software (FLACOS 2007).
[W1] J.G. Simonsen, "A Factorization Theorem in Higher-Order Rewriting with Application to Modular Reduction Semantics". Brazilian Symposium on Programming Languages (SBLP 2000).

Theses and technical reports

[D3] J.G. Simonsen, "On Computable Approximation of Infinite Objects". PhD dissertation.
[D2] J.G. Simonsen, "Higher-Order Rewriting with Applications to Impure Functional Languages". Speciale for the degree of cand. scient. (roughly equivalent to a master's thesis).
[D1] B.M. Andersen, J.G. Simonsen, "Kuglefunktioner" (Eng. "Spherical Harmonics"). Bachelor's thesis, in Danish.

Teaching

News

New projects to be announced.

Current teaching

Lecturer (course head) in Introduction to programming, fall 2009.
Lecturer (course head, but Rasmus Jensen is doing most of the actual work) in Grundlæggende datalogi, fall 2009. Part of the Faculty of Humanities' "Communication and IT" programme.
Coordinator of the Human-Centered Computing project seminar, fall 2009.

Master's theses and graduate projects

I have a portfolio of master's thesis topics related to my main research interests. A new list is coming soon!

Bachelor's theses

New list coming soon.

Previous teaching

Lecturer in Data and Algorithms, part of the IT and Cognition programme at the Faculty of humanities, fall 2008.
Lecturer (course head) in Introduction to programming, part of the IT and cognition programme and given jointly with the course IT and information retrieval at the Faculty of Humanities, fall 2007.
Lecturer (course head) in Computability and complexity from a programming Perspective, spring 2007.
Lecturer in Theory of science for computer scientists, spring 2007.
Lecturer in Functional programming, fall 2005, fall 2006, fall 2007, fall 2008 (course head)
Lecturer in IT and information retrieval (at the Center for Lang. Tech., Faculty of Humanities), fall 2006.
Lecturer in Mathematics and computation, fall 2005.
Lecturer (course head) in Computer-based mathematics and computation, fall 2003.
Teaching assistant in Discrete mathematics, Mathematics and computation, V-Programming languages, V-Databases, 1997--2001, and report grader for Datalogi 0GB, 2000.

Contact

Jakob Grue Simonsen
Department of Computer Science, University of Copenhagen (DIKU)
Universitetsparken 1, DK-2100 Copenhagen Ø, Denmark.

E-mail: simonsen-at-diku-dot-dk
Phone: (+45) 35 32 14 39
Fax: (+45) 35 32 14 01