Photo Kadi-Liis Koppel,

13-15 November 2019
Tallinn - Estonia

31st Nordic Workshop on Programming Theory, NWPT'19
Tallinn, Estonia, 13-15 November 2019

Call for Papers

The 31st Nordic Workshop On Programming Theory - NWPT'19 is hosted by Software Science Department at Tallinn University of Technology and will be held in the campus of Taltech.


Important dates

Submission of abstracts: 16 September26 September 2019
Notification: 4 October7 October 2019
Final version: 22 October 2019
Registration: 22 October 2019
Workshop: 13-15 November 2019

The NWPT series of annual workshops is a forum bringing together programming theorists from the Nordic and Baltic countries, but also from elsewhere.


Topics of interest include (but are not limited to)

  • semantics of programming languages,
  • programming language design and programming methodology,
  • programming logics,
  • formal specification of programs,
  • program verification,
  • program construction,
  • tools for program verification and construction
  • program transformation and refinement,
  • real-time and hybrid systems,
  • models of concurrency and distributed computing,
  • model-based testing
  • language-based security

Invited Speakers

A compositional approach to Signal Flow Graphs

Wednesday, November 13, 2019, 9:30-10:30

Paweł Sobociński

Tallinn Univ. of Technology, Estonia

Signal flow graphs are a classical state-machine model of computation first proposed by Claude Shannon, and are well-known in control theory and engineering. They have a continuous interpretation, where they compute solutions of systems of homogeneous higher-order differential equations, and a discrete interpretation, where they compute solutions of recurrence relations.

I will give a compositional presentation of the theory of signal flow graphs using standard techniques of programming language semantics. String diagrams provide a rigorous graphical syntax, and a denotational semantics is given as a monoidal functor to an appropriate category of linear relations. Operational semantics can be given using a structural presentation.

Denotational equality will be characterised: i) axiomatically, in terms of an equational theory that shows how the basic syntactic components “interact", ii) and in operational terms as contextual equivalence, via a full abstraction result that relies on recent work that extends the setting from linear to affine relations.


Interpreting and validating machine learning models

Thursday, November 14, 2019, 9:00-10:00

Ando Saabas (Bolt, Estonia)

Bolt, Estonia

Machine learning models are being increasingly used in practical applications, including in fields such as healthcare, manufacturing and transportation. These models, while powerful, can sometimes fail in very unintuitive ways. As the size and complexity of the models increases, it has become more and more important to understand the reasoning of the models, i.e. to validate that the interplay between specification (read: training data) and program (read: the model) is what was intended.

In this talk, I will give an overview of the state of the art in interpreting ML models. In particular, I will explain how tree based models such as random forests or gradient boosted trees can be instrumented to explain their predictions in terms of contributions from each feature in the input feature vector.


Two centuries of formal computation

Friday, November 15, 2019, 9:00-10:00

Jan von Plato

University of Helsinki, Finland

Theories of formal computation preceded actual programmable computers by about one hundred years. The first intimations of such computation go back even further, to one Johann Schultz, professor of mathematics and royal court-preacher in Kant's Königsberg, and to Leibniz. Google books and other online sources have made it possible to illustrate through original sources the long way from Leibniz' formal proof of 2 +2 = 4 to the 1930's that represented formal computation as a species of formal deduction.


Authors wishing to give a talk at the workshop are requested to submit abstracts of 2-3 pages (pdf, printable on A4 paper, using easychair.cls [zip]) through EasyChair ( by 16 26 September 2019. Work in progress as well as abstracts of manuscripts submitted for formal publication elsewhere are permitted. The abstracts accepted will be published electronically in the book of abstracts of the workshop. By submitting, you agree that, if your abstract is accepted, it will be published in this fashion. Moreover, you as the author are responsible for the content.

We have arranged a special issue of the Journal of Logical and Algebraic Methods in Programming (JLAMP) devoted to the best contributions to the workshop. The contributions will be selected by the PC. They will be invited after the workshop and will undergo a rigorous, journal-strength review process according to the standards of JLAMP.

Programme Committee

  • Antonis Achilleos, Reykjavík University, Iceland
  • Johannes Borgström, Uppsala Univ., Sweden
  • Martin Elsman, Univ. of Copenhagen, Denmark
  • Daniel S. Fava, Univ. of Oslo, Norway
  • John Gallagher, RUC, Denmark
  • Michael R. Hansen, DTU, Denmark
  • Magne Haveraaen, Univ. of Bergen, Norway
  • Keijo Heljanko, Univ. of Helsinki, Finland
  • Thomas T. Hildebrandt, DIKU, Denmark
  • Einar Broch Johnsen, Univ. of Oslo, Norway
  • Jaakko Järvi, Univ. of Bergen, Norway
  • Yngve Lamo, Western Norway Univ. of Applied Sciences, Norway
  • Alberto Lluch Lafuente, DTU, Denmark
  • Fabrizio Montesi, Univ. of Southern Denmark, Denmark
  • Wojciech Mostowski, Halmstad Univ., Sweden
  • Olaf Owe, Univ. of Oslo, Norway
  • Philipp Rümmer, Uppsala Univ., Sweden
  • Gerardo Schneider, University of Gothenburg, Sweden
  • Cristina Seceleanu, Mälardalen Univ., Sweden
  • Jiri Srba, Aalborg Univ., Denmark
  • Tarmo Uustalu, Reykjavík University, Iceland
  • Jüri Vain, Tallinn Univ. of Tech., Estonia
  • Antti Valmari, University of Jyväskylä, Finland
  • Marina Waldén, Åbo Akademi Univ., Finland

Organizing Committee

  • Jüri Vain (chair)
  • Tarmo Uustalu
  • Juhan Ernits
  • Marko Kääramees
  • Anu Baum
  • Monika Perkmann

from Tallinn University of Technology.

Contact email: nwpt2019(at)

Further Information

Further information will appear on, or can be obtained by mailing to the organizers at nwpt19(at)

NWPT 2019 page  © Taltech:NWPT'19   Last modified December 23, 2019 16:52 UTC by local organizers    Contact: