Author Archives: Jeremias

About Jeremias

I am a soon-to-be doctor of computer science from the University of Helsinki. My main research interests are NP-hard optimization problems and in particular constraint optimization. I am also interested in several areas of operations research and data analysis in general.

New Paper

Our paper: Computing Smallest MUSes of Quantified Boolean Formulas is now available on the webpage. This week Andreas is presenting it at the 16th International Conference on Logic Programming and Non-monotonic Reasoning (LPNMR) held in Genova Nervi, Italy.

The paper presents an algorithm for computing smallest unsatisfiable subsets (i.e. sources of inconsistency) of quantified Boolean formulas. Additionally, the paper proves that the complexity of doing so is sigma k+1 p complete for k quantifier blocks (i.e. very difficult, even for computers). The implementation of the algorithm used in our experiments is available on bitbucket. If you want to chat more about the topic, feel free to get in touch!

Thanks to all of my co-authors, Andreas, Jere and Matti.

New Position and Title

I am happy to let you know that tomorrow (on the 1.9.2022) I will start in a new position as a University Lecturer at the Department of Computer Science of the University of Helsinki. In practice this will (hopefully) mean that I will get the opportunity to teach some more in the future.

For a related (but separate) piece of news I have also recently been awarded the title of Docent of Computer Science from the University of Helsinki. Docent is a title that is a bit tricky to translate to English as it tends to have slightly different meanings in different countries. In Finland, it refers to someone with the right to teach their own subject at the University without having to be associated with the University (although often is).

I am grateful and honoured for both the position and the title. Thanks to the department of computer science and the University of Helsinki!

Back From FloC

After about two years of remote conferences I travelled last week to Haifa in Israel to attend the 8th federated logic conference (FLoC 2022) The trip consisted of meeting colleagues, hearing about their exiting research, and getting inspire. In the free time we explored the (very hilly) city of Haifa. The highlight of my trip was giving an invited talk at the SAT conference. I wrote about that in this blogpost.

I’d like to thank the organisers of FloC, as well as the organisers of the SAT conference. See you in 4 years!

Invited Talk at the SAT 2022 conference

Yesterday, on the 4th of August I gave an invited talk on Maximum Satisfiability at the “25 years of SAT” celebratory session of the 2022 SAT conference at Haifa in Israel. Mine was one of 5 talks, the others were given by Alexander Nadel, Armin Biere, Olaf Beyersdorff and Marijn Heule.

I would like to thank the session organiser, Prof. Jakob Nordström for the invite. I had a great time an am very honoured to have been considered together with such established researchers.

Research Visit To Brussels and Delft

In may this year I visited Prof. Bart Bogaerts at the Vrije Universiteit Brussel.. During the two week visit we talked about possible connections between our research. We were also joined by Jakob Nordström, his student Andy Oertel, and Ciaran McCreesh.
At the end of the visit, I also spent a day in Delft talking to Emir Demirović.

I’d like to thank Bart for hosting the visit and everyone else for the interesting discussions. I am looking forward to potential further collaboration.

Camera Ready Papers Available

The four papers accepted at Floc 2022 are now available from my publications page:

If you want to discuss any of these in more detail, let me know and I’d be happy to.
Once again, thanks to all my co-authors!

New Papers Accepted

I am pleased to let you know that my spring season of research ended with 4 papers accepted at FLoC 2022.
Three at the SAT conference:

  • MaxSAT-Based Bi-Objective Boolean Optimization with Christoph Jabs, Andreas Niskanen and Matti Jävisalo.
    • The paper describes a SAT-based approach for computing the pareto-front of biobjective optimization problems.
  • Improvements to the Implicit Hitting Set Approach to Pseudo-Boolean Optimization with Pavel Smirnov and Matti Järvisalo
    • The paper describes improvements to the implicit hitting set algorithm for pseudo-Boolean optimization that we proposed in last years CP conference.
  • Incremental Maximum Satisfiability with Andreas Niskanen and Matti Järvisalo
    • The paper describes an API for implementing incremental Maximum Satisfiability as well as a solver that implements it.

And the paper Clause Redundancy and Preprocessing in Maximum Satisfiability with Hannes Ihalainen and Matti Järvisalo at the IJCAR conference.

All of the papers will be available after the camera ready deadlines have passed. Let me know if you want to get a copy of them beforehand.

I’d like to thank all of my coauthors. See you at Haifa in August.

The Doctoral Program of CP 2021

Yesterday (October 25th) saw the culmination of one of my biggest projects of the year in the form of the Doctoral Program of the CP 2021 conference, which was chaired and organised by me.

The doctoral program is a full day even at the conference. The goal is to gather early-career (student) researchers in order to discuss ongoing research in a relaxed atmosphere. Additionally the DP aimed to provide opportunities for students to interact with more experienced researchers.

This year, the DP was a full day event held om 25th of October, the workshop day of the main conference. We had nine submissions from students. The program consisted of a discussion of the reviews submitted by the participants, two sessions for the participants to present their own work, and a panel discussion on presenting work with more senior researchers. The panelists were:
Professor Christine Solnon from INSA de Lyon
Professor Tias Guns from KU Leuven
Professor Susanna de Rezende from the Czech Academy of Sciences, Prague an
Royal Society Research Fellow and Reader Christopher Jefferson
from University of St. Andrews. The program concluded with a social session were we played codenames with the participants.

The videos of the contributions to the DP (including the panel) can be found on youtube (below). The submissions themselves can be found on Google Drive.

The recordings of the DP 2021

I would like to express my sincerest gratitude to everyone who contributed to the doctoral program, including all of the authors, the panelists and everyone who agreed to be on the program committee and provide the students with helpful comments.

While the DP is over, the conference itself is still going on. Two of my papers will still be presented today and the last one on Friday. If you’re interested you should definitely check it out, more info on the conference webpage.

First Workshop at the Junior University

During this year I have been a part of the steering group of a project called UniJunior. The aim of the project is to increase the curiosity of children in elementary school towards science and research by organising a series of interdisciplinary workshops in Swedish once per month during the fall and spring of 2021-2022. The project especially targets kids coming from non-academic homes. It is funded by Svenska Kulturfonden and Stiftelsen Brita Maria Renlunds minne.

Last Saturday the project kicked off with a workshop on colors, a workshop planned mainly be me and Christoffer Fridlund. The kids got to learn about what kind of a role color plays in different chemical reactions, how rainbows are formed by light refraction and how computers represent color as numbers. I thought the whole things went really well and—based on the feedback we collected—so did the kids!

I would especially like to thank Martina, Eva and Jim for planning, organising, and running the workshop with me and the ChemistryLab Gadolin for lending their premises and suplies for the workshop. I would also like to express my gratitude to everyone in the steering group of UniJunior, including its chair Prof. Gunilla Holm.

Three new publications accepted at CP 2021

I am happy to let you know that I had three papers accepted at CP 2021. More details on them (as well as the full versions) can be found on on the publications page on these webpages.
I would like to thank all my co-authors, especially Pavel and Hannes whose first papers these are. See you at the conference in October!

These papers also mark the beginning of my very own Academy of Finland project! I am looking forward to developing new optimisation algorithms that combine the strengths and weaknesses of many different paradigms and also work incrementally.