Reijo Jaakkola

Email: reijo.jaakkola[at]tuni.fi

Curriculum Vitae | LinkedIn

I'm a PhD student in mathematics at Tampere University, where I'm supervised by Antti Kuusisto and Lauri Hella.

My background is in the study of the satisfiability problems of fragments of first-order logic. More specifically, I have studied the computational complexities of the satisfiability problems of various fragments using the tools of computational complexity theory. Recently I have been focusing on fragments that are descentents of modal logics.

Currently I am also focusing on trying to understand algorithms and heuristics that are being used to solve real-life (industrial) instances of constraint satisfaction problems. This also naturally leads to the study of the average case complexity of these problems, since industrial instances can be seen as being selected according to some polynomial time samplable distribution.

Research interests: fragments of first-order logic, satisfiability problem, constructivism in mathematics.

Publications

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

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

  2. Complexity Classifications via Algebraic Logic [Preprint]

    Joint work with Antti Kuusisto.

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

  3. Explainability via Short Formulas: the Case of Propositional Logic with Implementation [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)

  4. Towards Model Theory of Ordered Logics: Expressivity and Interpolation [Preprint][Paper]

    Joint work with Bartosz Bednarczyk.

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

  5. Uniform Guarded Fragments [Preprint][Paper]

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

  6. Ordered Fragments of First-Order Logic [Preprint][Paper]

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

Preprints

  1. Convergence in the space of compact labeled metric spaces (Joint work with Antti Kykkänen.) [Preprint]
  2. Relating description complexity to entropy (Joint work with Antti Kuusisto and Miikka Vilander.) [Preprint]
  3. First-order logic with self-reference (Joint work with Antti Kuusisto.) [Preprint]
  4. An Extension of Trakhtenbrot's Theorem [Preprint]
  5. Complexity of the Ackermann fragment with one leading existential quantifier [Preprint]

Talks

  1. Nopeat algoritmit ja laskennallinen vaativuus teoria (Invited talk)

    [Slides in Finnish]

    IntegraatioFest 2022, October 28-30, Tampere (Finland)

  2. First-order logic with self-reference [Slides]

    PhDs in Logic XIII, September 5-7, 2022, Turin (Italy)

  3. Uniform Guarded Fragments [Slides]

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

  4. Complexity of Polyadic Boolean Modal Logics: Model Checking and Satisfiability

    Logic and discrete mathematics seminar, Tampere University, Finland, 25 March 2022

  5. 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

  6. Ordered fragments of first-order logic [Slides]

    Finnish Mathematical Days 2022

  7. What is a fragment? [Slides]

    Philosophy of Mathematics in Finland, Tampere, Finland, November 2021

  8. Interpolation and fragments of first-order logic

    Logic and discrete mathematics seminar, Tampere University, Finland, 24 September 2021

  9. Ordered fragments of first-order logic [Slides]

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

  10. Extensions of two-variable logic [Slides]

    Logic and discrete mathematics seminar, Tampere University, Finland, 11 December 2020

  11. Algebraic classifications for fragments of first-order logic and beyond [Slides]

    Logicians' Spring Gathering 2020, Tampere University, Finland, 8 May 2020

Thesis

  1. Algebraic Fragments of First-Order Logic [Thesis]

    Master's thesis, Tampere University, 2021, 45 pages

Awards

  1. 2022 Ernst Lindelöf Prize

    Awarded for the best master's thesis in mathematics written in Finland during the academic year 2021-2022.

Quotes

  1. But what we can't say we can't say, and we can't whistle it either.

    Frank Ramsey

  2. The method of showing a statement to be tautologous consists merely of constructing a table under it in the usual way and observing that the column under the main connective is composed entirely of 'T's.

    Willard V. O. Quine

  3. Young man, in mathematics you don't understand things. You just get used to them.

    John von Neumann

Self-portrait