Combinatorial Optimization and Logistics

The Combinatorial Optimization and Logistics (CSLog) group at the University of Bremen focuses on the analysis of discrete algorithmic problems that are computationally difficult. We analyze the structure of such problems and design efficient algorithms with provable performance guarantees for solving them. We are particularly interested in combinatorial optimization problems where the input is revealed only incrementally or where there is uncertainty in the parameters, and we develop online, stochastic or robust solution methods. Recently, we have focused on data-driven and learning-augmented methods.

Combinatorial optimization is related to theoretical computer science, discrete mathematics, operations research, algorithm theory and computational complexity theory and has important applications in several fields. In our group we develop theoretic results and apply them to complex real-world environments. Typical applications include scheduling, production planning, logistics, network design, communication and routing in networks, and health care.

Combinatorial Optimization and Logistics
Faculty 3: Mathematics & Computer Science
Prof. Dr. Nicole Megow

Bibliothekstr. 5
28359 Bremen

Secretary office
Caroline Mintert
Telefon: +49 (0) 421 218 63580

Research topics

approximation algorithms
online optimization
stochastic dynamic optimization
explorable uncertainty
learning-augmented algorithms
scheduling and resource management
network design and routing
logistics applications

Students sitting in the auditorium during a lecture

Teaching

Courses
Research seminar
Theses

Publications

groups publication list

Bremen-Hamburg Network

Bremen-Hamburg Initiative on Algorithms, Combinatorics and Optimization

ALPS@IJCAI 2026 in Bremen

Algorithms with Predictions

Open-source project dedicated to maintaining a repository for papers and links related to learning-augmented algorithms.

Prof. Dr. Nicole Megow

[Translate to English:] Bild von Moritz Buchem

Dr. Moritz Buchem

Dr. Sarah Morell

Dr. Maximilian Stahlberg

Dr. Michalis Xefteris

M.Sc. Bart Zondervan

M.Sc. Morten Weber

M.Sc. Joes Biburger

M.Sc. Golnoosh Shahkarami

Mar 25-26, 2026: Moritz, Nicole, Joes, and Morten take 8- to 12-year-olds on adventures through Algorithm Adventure Land at the Kinder-Uni Bremen.

Mar 23, 2026: Our paper "Protecting the Connectivity of a Graph under Non-uniform Edge Failures" (Felix Hommelsheim, Zhenwei Liu, Nicole Megow, Guochuan Zhang) has been accepted for publication in SIAM J. Discrete Mathematics.

Jan 17, 2026: Our paper "Polytope Scheduling with Groups: Unified Models and Optimal Guarantees" (Alex Lindermayr, Zhenwei Liu, Nicole Megow) has been accepted at IPCO 2026.

Jan 14, 2026: Our paper "The Power of Proportional Fairness for Non-Clairvoyant Polytope Scheduling" (Sven Jäger, Alex Lindermayr, Nicole Megow) has been accepted for publication at SIAM Journal on Computing.

Jan 1, 2026: Congratulations to Michalis Xefteris on receiving a two-year fellowship from the Alexander von Humboldt Foundation.

Jan 1, 2026: A warm welcome to our two new group members, Golnoosh Shakharami and Michalis Xefteris.

Dec 16, 2025: Our paper "On Solution Discovery via Reconfiguration" (Michael R. Fellows, Mario Grobler, Nicole Megow, Amer E. Mouawad, Vijayaragunathan Ramamoorthi, Frances A. Rosamond, Daniel Schmand, Sebastian Siebertz) has been accepted for publication in the Journal of Computer and System Sciences.

Dec 12, 2025: Our paper “Optimal Verification of a Minimum-Weight Basis in an Uncertainty Matroid” (Haya Diwan, Lisa Hellerstein, Nicole Megow, Jens Schlöter) got accepted at STACS 2026.

Dec 12, 2025: Our paper “A 13/6-Approximation for Strip Packing via the Bottom-Left Algorithm” (Stefan Hougardy, Bart Zondervan) got accepted at STACS 2026.

Dec 10-11, 2025: Bremen-Hamburg Colloquium on Algorithms, Combinatorics and Optimization

Nov 24, 2025: Our paper “On solution discovery via reconfiguration” (Michael R. Fellows, Mario Grobler, Nicole Megow, Amer E. Mouawad, Vijayaragunathan Ramamoorthi, Frances A. Rosamond, Daniel Schmand, Sebastian Siebertz) got accepted in Journal of Computer and System Sciences, Vol. 157, 2026.

Nov 16-21, 2025: Dagstuhl Seminar on Online Algorithms beyond Competitive Analysis (organized by Sungjin Im, Nicole Megow, Debmalya Panigrahi, Sahil Singla)

Nov 10-14, 2025: Sander Borst, Golnoosh Shahkarami, Karol Wegrzycki from MPII Saarbrücken are visiting our group.

October 17, 2025: Christina Metzogiannaki-Jost presents her Bachelor's thesis on "Makespan Minimization for Scheduling with Explorable Release Dates and Non-Uniform Query Cost" in the colloquium.

Oct 9, 2025: Nicole is invited to speak about "The Power of Two Oracles: Minimum Spanning Tree and Matroid Optimization" at the CWI Workshop on Learning Augmented Algorithms in Amsterdam.

October 1, 2025: A warm welcome to our new Phd student Morten Weber! He will work in the new Cluster of Excellence: The Martian Mindset: A Scarcity-Driven Engineering Paradigm

29 August, 2025: We’re saying goodbye to Alexander Lindermayr who is leaving our group. We wish him all the best in his postdoc at Simons Institute for the Theory of Computing at UC Berkeley. We'll stay connected!

July 8, 2025: Our paper "A Little Clairvoyance Is All You Need" (Anupam Gupta, Haim Kaplan, Alexander Lindermayr, Jens Schlöter, Sorrachai Yingchareonthawornchai) got accepted at FOCS 2025!

July 7, 2025: The ICALP 2025 Satellite Workshop on Theory and Applications of Algorithms with Predictions (TAAP25) is being organized by Spyros Angelopoulos, Antonios Antoniadis, Marek Eliáš, Lene Favrholdt, and Nicole Megow.

July 1-4, 2025: Nicole is speaking, and Bart and Morten are participating at the PhD School on Intersections of Algorithms and Machine Learning Theory, held in Odense, DK.

July 1, 2025: A warm welcome to our new postdoc Max Stahlberg and our new Phd student Joes Biburger!

June 11-13, 2025: IPCO 2025 took place at Johns Hopkins University in Baltimore, US, with Nicole as PC chair.

May 31, 2025: We’re saying goodbye to Felix Hommelsheim, who is leaving our group for a Postdoc in Santiago de Chile. Wishing him all the best, and we'll stay connected!

May 22, 2025: Great success for Bremen’s research community: the Cluster of Excellence The Martian Mindset has been approved, and we are proud to be part of it.

May 13-14, 2025: Bremen-Hamburg Colloquium on Algorithms, Combinatorics and Optimization at U Hamburg.

May 7, 2025: Felix gives a lecture on "Efficient Algorithms for Survivable Network Design" as a Junior Fellow of the Institute of Advanced Studies Hanse-Wissenschaftskolleg (HWK).

Apr 25, 2025: We’re saying goodbye to Zhenwei Liu, who is leaving our group to complete his PhD at Zhejian University. Wishing him all the best, and we'll stay connected!

Apr 1, 2025: Sarah Morell joins our group as a postdoc.

Mar 31 - Apr 4, 2025: Svenja Griesbach (CMM, Santiago de Chile) is visiting our group.

Mar 25, 2025: Nicole speaks about "Query Minimization for Stochastic Selection Problems" at the Dagstuhl Seminar on Approximation Algorithms for Stochastic Optimization .

Mar 18, 2025: Alex speaks about "A Little Clairvoyance Is All You Need for Minimizing Total Flow Time" at the Dagstuhl Seminar on Scheduling and Fairness.

Mar 16-21, 2025: Dagstuhl Seminar on Scheduling and Fairness organized by Claire Mathieu, Nicole Megow, Ben Moseley, Frits Spieksma

Mar 4, 2025: Zhenwei speaks about "Protecting the Connectivity of a Graph under Non-uniform Edge Failures" at STACS 2025

Feb 01, 2025: Our paper "A 5/4-Approximation for Two-Edge Connectivity" (Miguel Bosch-Calvo, Mohit Garg, Fabrizio Grandoni, Felix Hommelsheim, Afrouz Jabal Ameli and Alexander Lindermayr)got accepted at STOC 2025!

Jan 14, 2025: Alex speaks about "The Power of Proportional Fairness for Non-Clairvoyant Scheduling under Polyhedral Constraints" at SODA 2025.