Reijo Jaakkola

About Me

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Welcome!

I'm a fourth year PhD student in mathematics at Tampere University, where I'm supervised by Antti Kuusisto and Lauri Hella. My interests today are broadly in theoretical computer science, mathematical logic and machine learning.

Publications

Peer-reviewed

  1. Relating Description Complexity to Entropy [Publication]

    Joint work with Antti Kuusisto and Miikka Vilander

    Journal of Computer and System Sciences

    Journal version of this conference paper.

  2. Description Complexity of Unary Structures in First-Order Logic with Links to Entropy [Preprint]

    Joint work with Antti Kuusisto and Miikka Vilander

    Computer Science Logic 2025, February 10-14, 2025, Amsterdam, Netherlands

  3. Interpretable Classifiers for Tabular Data via Feature Selection and Discretization [Publication] [Preprint]

    Joint work with Tomi Janhunen, Antti Kuusisto, Masood Feyzbakhsh Rankooh and Miikka Vilander

    4th International Workshop of Data meets Applied Ontologies in Explainable AI, October 19, 2024, Santiago de Compostela, Spain

  4. Short Boolean Formulas as Explanations in Practice [Publication] [Preprint]

    Joint work with Tomi Janhunen, Antti Kuusisto, Masood Feyzbakhsh Rankooh and Miikka Vilander

    18th Edition of the European Conference on Logics in Artificial Intelligence, September 20-22, 2023, Dresden, Germany

  5. Relating Description Complexity to Entropy [Publication] [Preprint]

    Joint work with Antti Kuusisto and Miikka Vilander

    40th International Symposium on Theoretical Aspects of Computer Science, March 7-10, 2023, Hamburg, Germany

  6. Complexity of Polyadic Boolean Modal Logics: Model Checking and Satisfiability [Publication] [Preprint]

    Computer Science Logic 2023, February 13-16, 2023, Warsaw, Poland

  7. Complexity Classifications via Algebraic Logic [Publication] [Preprint]

    Joint work with Antti Kuusisto

    Computer Science Logic 2023, February 13-16, 2023, Warsaw, Poland

  8. Explainability via Short Formulas: the Case of Propositional Logic with Implementation [Publication] [Preprint]

    Joint work with Tomi Janhunen, Antti Kuusisto, Masood Feyzbakhsh Rankooh and Miikka Vilander

    29th RCRA International Workshop on "Experimental Evaluation of Algorithms for solving problems with combinatorial explosion", September 5, 2022, Genova, Italy

  9. Towards Model Theory of Ordered Logics: Expressivity and Interpolation [Publication] [Preprint]

    Joint work with Bartosz Bednarczyk

    47th International Symposium on Mathematical Foundations of Computer Science, August 22-26, 2022, Vienna, Austria

  10. Uniform Guarded Fragments [Publication] [Preprint]

    25th International Conference on Foundations of Software Science and Computation Structures, April 2-7, 2022, Munich, Germany

  11. Ordered Fragments of First-Order Logic [Publication] [Preprint]

    46th International Symposium on Mathematical Foundations of Computer Science, August 23-27, 2021, Tallinn, Estonia

Preprints

  1. A monotone connection between model class size and description length [Preprint]

    Joint work with Antti Kuusisto and Miikka Vilander

  2. Convergence in the space of compact labeled metric spaces [Preprint]

    Joint work with Antti Kykkänen

  3. First-order logic with self-reference [Preprint]

    Joint work with Antti Kuusisto

Notes

  1. An Extension of Trakhtenbrot's Theorem [Read Note]
  2. Complexity of the Ackermann fragment with one leading existential quantifier [Read Note]

Talks

  1. Description complexity - Slides
    Seminar for young researchers, University of Jyväskylä, Finland, 27 November 2024
  2. Uniform guarded fragments: interpolation and complexity - Slides
    Workshop on Theory and Applications of Craig Interpolation and Beth Definability, April 22-23, 2024, Amsterdam, Netherlands
  3. Formulas of propositional logic as interpretable classifiers - Slides
    Mathematical Perspective on Machine Learning, University of Helsinki, Finland, 9 April 2024
  4. Why do overparameterized neural networks generalize? - Slides
    Seminar for young researchers, University of Jyväskylä, Finland, 6 March 2024
  5. Explaining Classifiers and Data via Propositional Logic - Slides
    Logic seminar, University of Helsinki, Finland, 22 November 2023
  6. First-Order Logic with Game-Theoretic Recursion - Slides
    Logic seminar, University of Helsinki, Finland, 20 April 2023
  7. The Asymptotic Equipartition Property
    Seminar for young researchers, University of Jyväskylä, Finland, 29 March 2023
  8. Relating Description Complexity to Entropy - Slides
    Research Seminar Logic and AI, TU Dresden, March 16, 2023, Dresden, Germany
  9. First-Order Logic with Game-Theoretic Recursion - Slides
    Fixed Points in Computer Science 2023, February 17, 2023, Warsaw, Poland
  10. Complexity of Polyadic Boolean Modal Logics: Model Checking and Satisfiability - Slides
    Computer Science Logic 2023, February 13-16, 2023, Warsaw, Poland
  11. Complexity Classifications via Algebraic Logic - Slides
    Computer Science Logic 2023, February 13-16, 2023, Warsaw, Poland
  12. First order logic with game-theoretic recursion II
    Logic and discrete mathematics seminar, Tampere University, Finland, 13 January 2023
  13. Nopeat algoritmit ja laskennallinen vaativuus teoria (Invited talk) - Slides in Finnish
    IntegraatioFest 2022, October 28-30, Tampere, Finland
  14. First-order logic with self-reference - Slides
    PhDs in Logic XIII, September 5-7, 2022, Turin, Italy
  15. Uniform Guarded Fragments - Slides
    25th International Conference on Foundations of Software Science and Computation Structures, April 2-7, 2022, Munich, Germany
  16. Complexity of Polyadic Boolean Modal Logics: Model Checking and Satisfiability
    Logic and discrete mathematics seminar, Tampere University, Finland, 25 March 2022
  17. Undecidability of the Halting Problem and Gödel's Incompleteness Theorems - Slides - Video
    What is Computation? From Turing Machines to Black Holes and Neurons, Harvard GSAS Mini-Course, January 2022
    Course website
  18. Ordered fragments of first-order logic - Slides
    Finnish Mathematical Days 2022
  19. What is a fragment? - Slides
    Philosophy of Mathematics in Finland, Tampere, Finland, November 2021
  20. Interpolation and fragments of first-order logic
    Logic and discrete mathematics seminar, Tampere University, Finland, 24 September 2021
  21. Ordered fragments of first-order logic - Slides
    46th International Symposium on Mathematical Foundations of Computer Science, Tallinn, Estonia, August 2021
  22. Extensions of two-variable logic - Slides
    Logic and discrete mathematics seminar, Tampere University, Finland, 11 December 2020
  23. Algebraic classifications for fragments of first-order logic and beyond - Slides
    Logicians' Spring Gathering 2020, Tampere University, Finland, 8 May 2020

Theses

  • Algebraic Fragments of First-Order Logic - [Thesis]
    Master's thesis, Tampere University, 2021
  • Awards

  • Best Tech Solution - Unlocking ESG Insights
    Hanken Quantum Hackathon 2023 [Website]
  • 2022 Ernst Lindelöf Prize
    Awarded for the best master's thesis in mathematics written in Finland during the academic year 2021-2022.
  • Professional Services

  • I organized a session for Young Researchers at the Finnish Mathematical Days 2024. The goal of the session was twofold: (1) to provide an opportunity for PhD students to present their research area within mathematics; and (2) to showcase modern research topics in mathematics within Finland. List of talks can be found here.
  • I have been a reviewer for various conferences (AAMAS 2022, IJCAI 2023, KR 2023, MFCS 2023, JELIA 2023, GandALF 2023, AAAI 2024, LICS 2024, KR 2024, AAMAS 2025) and journals (LMCS).
  • Software

  • RSCLASSIFIER - [Download]

    A Python library which implements a machine learning algorithm for learning role set classifiers for classification tasks. Easy to use, efficient and produces highly interpretable and transparent models.

  • Cont-Bouchand model - [Repository]

    Course project that I did for the course Statistical Physics 2.

  • Quotes that I Like

    "But what we can't say we can't say, and we can't whistle it either." – Frank Ramsey
    "Young man, in mathematics you don't understand things. You just get used to them." – John von Neumann
    "Bad ideas is good, good ideas is terrific, no ideas is terrible." – Leonard E. Baum