My research tackles questions rooted in both computational geometry and graph theory. During my predoctoral studies, I focused primarily on problems where grid graphs served as a crucial structure. Recently, however, I got more and more interested in questions that concern configurations and arrangements of discrete objects in the plane (and are not required to rely on grid points) from a large variety of viewpoints.

Short CV

• since September 2024: PostDoc Department of Discrete Mathematics, University of Kassel
• 2023-2024: PostDoc, Department of Computer Science, Algorithms division, TU Braunschweig
• 2016-2023: PreDoc, Department of Computer Science, Algorithms division, TU Braunschweig

Research interests

• Graph theory
• Discrete mathematics
• Algorithms
• Computational geometry
• Computational complexity theory
• Art Gallery problems
• Reconfiguration
• Flip graphs
• Motion planning

Publications

See also dblp or google scholar
• Counterexample to Winkler's conjecture on Venn diagrams
  with Sofia Brenner, Linda Kleist, Torsten Mütze, and Francesco Verciani.
  arXiv: 2503.18554
• Moving matter: Using a single, simple robot to reconfigure a connected set of building blocks
  with Javier Garcia, Jonas Friemel, Ramin Kosfeld, Michael Yannuzzi, Peter Kramer, Christian Scheffer, Arne Schmidt, Harm Kube, Dan Biediger, Sándor Fekete, and Aaron Becker.
• Guarding offices with maximum dispersion
  with Sándor P. Fekete, Kai Kobbe, Dominik Krupke, Joseph S. B. Mitchell, and Christian Scheffer.
• Drainability and fillability of polyominoes in diverse models of global control
  with Sándor P. Fekete, Peter Kramer, Jan-Marc Reinhardt, and Christian Scheffer.
• Segment watchman routes
  with Anna Brötzner, Omrit Filtser, Bengt J. Nilsson, and Christiane Schmidt.
  Short preprint in the 41st European Workshop on Computational Geometry (EuroCG 2025)
• Moving matter: Efficient reconfiguration of tile arrangements by a single active robot
  with Aaron T. Becker, Sándor P. Fekete, Jonas Friemel, Ramin Kosfeld, Peter Kramer, Harm Kube, Christian Scheffer, and Arne Schmidt.
  Short preprint in the 41st European Workshop on Computational Geometry (EuroCG 2025)
  arXiv: 2502.09299
• Sliding squares in parallel
  with Hugo A. Akitaya, Sándor P. Fekete, Peter Kramer, Saba Molaei, Frederick Stock, and Tobias Wallner.
  Short preprint in the 41st European Workshop on Computational Geometry (EuroCG 2025)
  arXiv: 2412.05523
• Getting better all the time? Harmonic and cumulative traveling salesman problems
  with Sándor P. Fekete, Dominik Krupke, Arne Schmidt, and Tobias Wallner.
  Short preprint in the 41st European Workshop on Computational Geometry (EuroCG 2025)
• Facet-Hamiltonian cycles in the B-permutahedron
  with Nastaran Behrooznia, Sofia Brenner, Arturo Merino, Torsten Mütze, and Francesco Verciani.
  arXiv: 2412.02584
• Coordinated motion planning: Multi-agent path finding in a densely packed, bounded domain
  with Sándor P. Fekete, Ramin Kosfeld, Peter Kramer, Jonas Neutzner, and Christian Scheffer.
  In proceedings of the 35th International Symposium on Algorithms and Computation (ISAAC 2024)
  arXiv: 2409.06486
• Dispersive vertex guarding for simple and non-simple polygons
  with Sándor P. Fekete, Joseph S. B. Mitchell, Christian Scheffer, and Christiane Schmidt.
  In proceedings of the 36th Canadian Conference on Computational Geometry (CCCG 2024)
  arXiv: 2406.05861
• On the connectivity of the flip graph of plane spanning paths
  with Linda Kleist and Peter Kramer.
  In proceedings of the 50th International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2024)
  arXiv: 2407.03912
• Reconfiguration of a 2d structure using spatio-temporal planning and load transferring
  with Javier Garcia, Michael Yannuzzi, Peter Kramer, Sándor P. Fekete, and Aaron T. Becker.
  In proceedings of the 41st International Conference on Robotics and Automation (ICRA 2024)
  arXiv: 2211.09198
• Guarding polyominoes under k-hop visibility
  with Omrit Filtser, Erik Krohn, Bengt J. Nilsson, and Christiane Schmidt.
  Journal version: Algorithmica, special issue of selected papers from LATIN 2024
  In proceedings of the 16th Latin American Symposium on Theoretical Informatics (LATIN 2024)
  arXiv: 2308.00334
• The lawn mowing problem: From algebra to algorithms
  with Sándor P. Fekete, Dominik Krupke, Michael Perk, and Christian Scheffer.
  In proceedings of the 31st European Symposium on Algorithms (ESA 2023)
  Short preprint in the 39th European Workshop on Computational Geometry (EuroCG 2023)
  arXiv: 2307.01092
• Guarding and reconfiguration — Computational complexity and algorithm design
  Ph.D thesis, TU Braunschweig. 2023.
• A closer cut: Computing near-optimal lawn mowing tours
  with Sándor P. Fekete, Dominik Krupke, Michael Perk, and Christian Scheffer.
  In proceedings of the 25th Symposium on Algorithm Engineering and Experiments (ALENEX 2023), awarded as Best Paper of ALENEX 2023
  arXiv: 2211.05891
• The dispersive art gallery problem
  with Christian Scheffer.
  Journal version: Computational Geometry: Theory and Applications (CGTA), special issue of selected papers from ISAAC 2022
  In proceedings of the 33rd International Symposium on Algorithms and Computation (ISAAC 2022)
  arXiv: 2209.10291
• Efficiently reconfiguring a connected swarm of labeled robots
  with Sándor P. Fekete, Peter Kramer, Christian Scheffer, and Arne Schmidt.
  Journal version: Autonomous Agents and Multi-Agent Systems (JAAMAS)
  In proceedings of the 33rd International Symposium on Algorithms and Computation (ISAAC 2022)
  arXiv: 2209.11028
• Connected reconfiguration of polyominoes amid obstacles using RRT*
  with Javier Garcia, Michael Yannuzzi, Peter Kramer, and Aaron T. Becker.
  In proceedings of the 35th International Conference on Intelligent Robots and Systems (IROS 2022)
  arXiv: 2207.01282
• Space ants: Episode II - Coordinating connected catoms (multimedia)
  with Julien Bourgeois, Sándor P. Fekete, Ramin Kosfeld, Peter Kramer, Benoît Piranda, and Christian Scheffer.
  In proceedings of the 38th International Symposium on Computational Geometry (SoCG 2022)
  Video: YouTube
• Connected coordinated motion planning with bounded stretch
  with Sándor P. Fekete, Phillip Keldenich, Ramin Kosfeld, and Christian Scheffer.
  Journal version: Autonomous Agents and Multi-Agent Systems (JAAMAS)
  In proceedings of the 32nd International Symposium on Algorithms and Computation (ISAAC 2021)
  Short preprint in the 36th European Workshop on Computational Geometry (EuroCG 2020)
  arXiv: 2109.12381
• Particle-based assembly using precise global control
  with Jakob Keller, Christian Scheffer, and Arne Schmidt.
  Journal version: Algorithmica
  In proceedings of the 17th Algorithms and Data Structures Symposium (WADS 2021)
  arXiv: 2105.05784
• Space ants: Constructing and reconfiguring large-scale structures with finite automata (multimedia)
  with Amira Abdel-Rahman, Aaron T. Becker, Daniel Biediger, Kenneth C. Cheung, Sándor P. Fekete, Neil A. Gershenfeld, Sabrina Hugo, Benjamin Jenett, Philipp Keldenich, Eike Niehs, Christian Scheffer, Arne Schmidt, and Michael Yannuzzi.
  In proceedings of the 36th International Symposium on Computational Geometry (SoCG 2020)
  Video: YouTube
• Targeted drug delivery: Algorithmic methods for collecting a swarm of particles with uniform, external forces
  with Aaron T. Becker, Sándor P. Fekete, Li Huang, Phillip Keldenich, Linda Kleist, Dominik Krupke, and Arne Schmidt.
  In proceedings of the 37th International Conference on Robotics and Automation (ICRA 2020)
  Short preprint in the 36th European Workshop on Computational Geometry (EuroCG 2020)
  arXiv: 2408.09729
• Don't rock the boat: Algorithms for balanced dynamic loading and unloading
  with Sándor P. Fekete, Sven von Höveling, Joseph S. B. Mitchell, Christian Scheffer, Arne Schmidt, and James Zuber.
  In proceedings of the 13th Latin American Symposium on Theoretical Informatics (LATIN 2018)
  Short preprint in the 34th European Workshop on Computational Geometry (EuroCG 2018)
  arXiv: 1712.06498
  
• Tilt assembly: Algorithms for micro-factories that build objects with uniform external forces
  with Aaron T. Becker, Sándor P. Fekete, Phillip Keldenich, Dominik Krupke, Christian Scheffer, and Arne Schmidt.
  Journal version: Algorithmica, special issue of selected papers from ISAAC 2017
  In proceedings of the 28th International Symposium on Algorithms and Computation (ISAAC 2017)
  arXiv: 1709.06299
• On the traveling salesman problem in solid grid graphs
  with Sándor P. Fekete and Christian Scheffer.
  Short preprint in the 33rd European Workshop on Computational Geometry (EuroCG 2017)

Teaching

• Discrete mathematics 2 (Winter 2024/2025, Master's course in mathematics)
  I offer this self-designed course at the University of Kassel. The content has flavors from discrete mathematics, combinatorics, and discrete and computational geometry.
  Keywords: Polygons, Triangulations, Art Gallery Problem, Point sets, Convex hull, Voronoi diagram, Flip graphs, Geometric graph recognition, Visibility graphs, Hamiltonian cycles, ...

Teaching (assistant)

Network algorithms:	2021 / 2020 / 2019 / 2018 / 2017
Computational geometry:	2021 / 2020 / 2019
Linear programming:	2016
Algorithms and data structures:	2018 / 2017
Seminar:	2023 (S,W) / 2022 (S) / 2021 (S,W) / 2020 (S,W) / 2019 (S,W) / 2018 (S,W) / 2017 (S,W) / 2016 (W)

Supervised theses

Bachelor:	The capacitated lawn mowing problem
Bachelor:	Coordinated motion planning in three dimensions
Bachelor:	On flipping trees
Project:	Guarding practically motivated polygons with maximum dispersion
Bachelor:	Paths and tours in dynamic chessboard-like graphs
Master:	Efficient reconfiguration in the parallel sliding particle model
Bachelor:	Reconfiguration of graph colorings
Bachelor:	Coordinated reconfiguration with spatial separation
Bachelor:	Coordinated motion planning in restricted domains
Bachelor:	Reconfiguring tile arrangements by robots
Master:	Guarding with priorities
Bachelor:	Variants of the ordered path problem
Master:	Scanning polygons with mobile guards
Master:	Flip graphs of non-crossing configurations in the plane
Project:	Discrete reconfiguration problems -- overview and open problems
Bachelor:	Algorithmic methods for new variants of the traveling salesman problem
Master:	Reinforcement learning approaches for dynamic packing with gravity constraints (canceled)
Master:	Algorithmic methods for coordinated motion planning with multiple targets
Bachelor:	Single step tilt assembly with multiple seeds
Bachelor:	Computing outerplanar vertex partitions
Master:	Theoretical and practical approaches for optimizing lawn mowing and milling
Bachelor:	New approaches to geometric reconfiguration problems under connectivity constraints
Master:	Manipulating three-dimensional lattice-based cellular structures by finite automata (canceled)
Bachelor:	Geometric algorithms for special cases of connected unlabeled robot motion planning
Bachelor:	Variations and extentions of the two guards problem
Master:	New variants of the tilt assembly problem
Bachelor:	Methoden für dynamisch balancierte Packprobleme (in German)
Project:	Variants of the watchman problem
Bachelor:	Algorithmische Ansätze für energiebeschränkte Art-Gallery-Probleme (in German)
Bachelor:	Algorithmen für dynamisch balancierte Rekonfigurationsprobleme (in German)
Bachelor:	New variants of the floodlight problem
Bachelor:	Dispersive art gallery problems
Master:	Online covering with scan and travel cost
Bachelor:	Verteilte Algorithmen zur Objekterkennung mit Smart Pixeln (in German)