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Postdoc at Technical University of Denmark
Postdoc at Technical University of Denmark
About me
About me
Hi! I am Lasse Wulf, currently a postdoc under Eva Rotenberg in the Section for Algorithms, Logic, and Graphs at the Technical University of Denmark, Copenhagen. Recently, I obtained my PhD from Graz Institute of Technology, under the supervision of Bettina Klinz.
Broadly speaking, my research interests are centered around combinatorial optimization, algorithms, graph theory and complexity theory. More specifically, I am currently working on several problems regarding robust optimization, Sigma-2-complexity, interdiction problems, spanning tree packing, and derandomizing the Exact Matching problem.
Together with my coauthors, I received the best student paper award at IWOCA2021. I recently received the best dissertation award from the Austrian Society of Operations Research (ÖGOR).
Before starting my PhD, I obtained a double master's degree in mathematics and computer science from Karlsruhe Institute of Technology, Germany, in 2019. I also received a "Deutschlandstipendium" scholarship.
In my free time, I enjoy playing and improvising jazz piano and going climbing/bouldering.
[dblp] [Google Scholar] [ lawu (at) dtu (dot) dk ]
Curriculum Vitae
Curriculum Vitae
03/2024 - present: Postdoc at the Algolog Section at the Technical University of Denmark. Advised by Eva Rotenberg.
04/2022 - 07/2022 - Research visit at ETH Zurich, Switzerland. Visiting the groups of Emo Welzl, Bernd Gärtner and Rico Zenklusen
2019 – 2024: PhD student at Graz Institute of Technology, under the supervision of Bettina Klinz. Part of the Doctoral Program "Discrete Mathematics" funded by the Austrian Science Fund (FWF).
09/2016 – 09/2019: Double master's degree in mathematics and computer science at Karlsruhe Institute of Technology (KIT). Masterthesis advised by Torsten Ueckerdt.
09/2013 – 09/2016: Bachelor's degree in computer science at Karlsruhe Institute of Technology (KIT). Bachelorthesis advised by Torsten Ueckerdt and Ignaz Rutter.
Awards and Scholarships
Awards and Scholarships
01/2025 - Doctoral School Award from the Doctoral School "Mathematics and Scientific Computing" at TU Graz
08/2024 - Best dissertation award from the Austrian Society of Operations Research (ÖGOR).
05/2021 - Best student paper award at IWOCA2021 for the paper 'non-preemptive tree packing'. Together with S. Lendl and G. Woeginger.
10/2014 – 09/2018: Recipient of the "Deutschlandstipendium" scholarship at KIT. Funded alternatingly by the Vector Foundation, by private Alumni Christoph Felix and by the "Begabtenstiftung Informatik Karlsruhe".
09/2017: First place in the Automatic Category at the 25th International Symposium on Graph Drawing and Network Visuaization (GD 2017). Together with Almut Demel, Dominik Dürrschnabel, Tamara Mchedlidze and Marcel Radermacher.
04/2015: Winner of the German National Finals in the category "Games", Imagine Cup 2015. Together with Eric Klappert, Nicklas Kulp, and Jannik Prinz.
02/2014: German Bundeswettbewerb Mathematics. (Participant in the final round.)
09/2013: German Bundeswettbewerb Computer Science. (Participant in the final round and awardee.)
Talks
Talks
06.2025: A large and natural Class of Sigma-2- and Sigma-3-complete Problems in Bilevel and Robust Optimization. IPCO2025
05.2025: Fréchet Distance in Unweighted Planar Graphs. EuroCG25
02. 2025: A large and natural Class of Sigma-2- and Sigma-3-complete Problems in Bilevel and Robust Optimization. Robust Optimization Webinar
06. 2024: A large and natural Class of Sigma-2- and Sigma-3-complete Problems in Bilevel and Robust Optimization. EURO2024, Copenhagen
06. 2024: A large and natural Class of Sigma-2- and Sigma-3-complete Problems in Bilevel and Robust Optimization. ARCO2024, Copenhagen
03. 2024: Some recent advances on the Exact Matching Problem, AlgoLog Seminar, Technical University of Denmark
10. 2023 Some recent advances on the Exact Matching Problem. University of Bonn
10. 2023 A large and natural Class of Sigma-2- and Sigma-3-complete Problems in Bilevel and Robust Optimization. University of Passau
06. 2023 A linear time algorithm for linearizing quadratic and higher-order shortest path problems. 24th Conference on Integer Programming and Combinatorial Optimization (IPCO23), University of Wisconsin-Madison, Wisconsin
09. 2022: Exact Matching and Top-k Perfect Matching. 25th Workshop on Future Research in Combinatorial Optimization (FRICO25), Bonn University, Germany
09. 2022: On the Complexity of Robust Multi-Stage Problems in the Polynomial Hierarchy. International Conference on Operations Research (OR2022), KIT Karlsruhe
04. 2022: Non-preemptive tree packing. Mittagsseminar, ETH Zurich
09. 2021: Recoverable Robust Representatives Selection Problems with Discrete Budgeted Uncertainty. International Conference on Operations Research (OR2021), University of Bern
07. 2021: Non-preemptive tree packing. 32nd International Workshop on Combinatorial Algorithms (IWOCA 2021), University of Ottawa
06. 2021: Linearizable special cases of the quadratic shortest path problem. 47th International Workshop on Graph-Theoretic Concepts in Computer Science (WG21), University of Warsaw
01. 2021: Assistance and Interdiction Problems on Interval Graphs. Advanced Topics Seminar, TU Graz.
12. 2020: Recoverable Robust Representatives Selection Problems with Discrete Budgeted Uncertainty. Doctoral School Seminar, TU Graz.
10. 2020: Recoverable Robust Representatives Selection Problems with Discrete Budgeted Uncertainty. Online Seminar "Robust Optimization" of Dick den Hertog, Tilburg University.
07. 2020: Keeping a graph connected via nonpreemptive edge scheduling (Maximizing the minimum load time in a graphic matroid). Work group Seminar "Optimization", TU Graz.
05. 2020: On the Computational Complexity of the Game Top Trumps. Work group Seminar "Optimization", TU Graz.
Attended Conferences and PhD Schools
Attended Conferences and PhD Schools
06.2025: IPCO2025, John Hopkins University
05.2025: EuroCG 2025, Charles University Prague
06. 2024: 33rd European Conference on Operational Research (EURO24), Technical University of Denmark
06. 2023 24th Conference on Integer Programming and Combinatorial Optimization (IPCO23), University of Wisconsin-Madison, Wisconsin
09. 2022: 25th Workshop on Future Research in Combinatorial Optimization (FRICO25), Bonn University, Germany
09. 2022: International Conference on Operations Research (OR2022), KIT Karlsruhe, Germany
07. 2022: Bernoulli Center Summer School on Modern Trends in Combinatorial Optimization, EPFL Lausanne, Switzerland
07. 2022: Swedish Summer School in Computer Science (S3CS), KTH university Stockholm, Sweden
09. 2021: International Conference on Operations Research (OR2021) (online event)
07. 2021: 32nd International Workshop on Combinatorial Algorithms (IWOCA 2021) (online event)
06. 2021: 47th International Workshop on Graph-Theoretic Concepts in Computer Science (WG21) (online event)
05. 2021: School in Algorithms, Combinatorics, and Complexity (online event)
05. 2022: IPCO 2021 Summer School (online event)
08. 2020: Prague Summer School on Discrete Mathematics 2020 (online event)
06. 2020: IPCO 2020 summer school (online event)
Publications
Publications
[21]
Computing the Polytope Diameter is Even Harder than NP-hard (Already for Perfect Matchings)
Lasse Wulf
To appear: FOCS 2025
[20]
On Finding l-th Smallest Perfect Matchings
with Nicolas El Maalouly, Sebastian Haslebacher, Adrian Taubner
To appear: ESA 2025
[19]
Fréchet Distance in Unweighted Planar Graphs
with Ivor van der Hoog, Thijs van der Horst, Eva Rotenberg
To appear: ESA 2025
[18]
[17]
On the Complexity of the Bilevel Shortest Path Problem
with Dorothee Henke
To appear: Networks
[16]
On the Complexity of Recoverable Robust Optimization in the Polynomial Hierarchy
with Christoph Grüne
arXiv preprint, 2024
[15]
Completeness in the Polynomial Hierarchy for many natural Problems in Bilevel and Robust Optimization
with Christoph Grüne
26th Conference on Integer Programming and Combinatorial Optimization (IPCO), 2025
[14]
Recognition of Unit Segment and Polyline Graphs is ER-Complete
with Michael Hoffmann, Tillmann Miltzow, and Simon Weber
WG 2024
[13]
On the Exact Matching Problem in Dense Graphs
with S. Haslebacher and NE Maaouly
STACS 2024
[12]
An Approximation Algorithm for the Exact Matching Problem in Bipartite Graphs
with A. Dürr and NE Maalouly
APPROX 2023
[11]
A linear time algorithm for linearizing quadratic and higher-order shortest path problems
with E. Çela, B. Klinz, S. Lendl, and G. J. Woeginger
24th Conference on Integer Programming and Combinatorial Optimization (IPCO), 2023
[10]
[9]
On the complexity of robust multi-stage problems with discrete recourse
With M. Goerigk and S. Lendl
Discrete Applied Math, 2023
[8]
Exact Matching: Correct Parity and FPT parameterized by Independence Number
With NE Maalouly and R. Steiner
34th International Symposium on Algorithms and Computation (ISAAC), 2023
[7]
[6]
Two-Stage Robust Optimization Problems with Two-Stage Uncertainty
With M. Goerigk and S. Lendl
European Journal of Operational Research (EJOR), 2022
[5]
With S. Lendl and G. Woeginger
[conference] 32nd International Workshop on Combinatorial Algorithms (IWOCA), 2021
Best student paper award.
[journal] Algorithmica, 2022
[4]
Assistance and Interdiction Problems on Interval Graphs
With H. P. Hoang and S. Lendl
Discrete Applied Math, 2023
[3]
Linearizable special cases of the quadratic shortest path problem
With E. Çela, B. Klinz, S. Lendl, J. B. Orlin, and G. J. Woeginger
International Workshop on Graph-Theoretic Concepts in Computer Science (WG), 2021
[2]
Recoverable Robust Representatives Selection with Discrete Budgeted Uncertainty
With M. Goerigk and S. Lendl
European Journal of Operational Research (EJOR), 2022
[1]
A greedy heuristic for crossing-angle maximization.
With A. Demel, D. Dürrschnabel, T. Mchedlidze and M. Radermacher
International Symposium on Graph Drawing and Network Visualization (GD), 2018
[PhD]
PhD Thesis
Graz University of Technology
Contact: lawu (at) dtu (dot) dk
Contact: lawu (at) dtu (dot) dk
Richard Petersens Plads, Building 322, Office 005
2800 Kgs. Lyngby
In order to contact me, feel free to write me an email or drop by my office :)
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