- Graphs & Geometry
- Computational Geometry
- Computational Complexity
- Discrete Mathematics
- Geometric Optimization Problems
- Packing Problems
- Area-Universality
- Reconfiguration and Flip Graphs
Recent and Upcoming Events
- Eleventh Annual Workshop on Geometry and Graphs, Barbados
- Dagstuhl seminar: Triangulations in Geometry and Topology, Schloss Dagstuhl
- Oberwolfach seminar, Oberwolfach
- Symposium on Computational Geometry, speaker for Geometric Embeddability of Complexes is ∃R-complete
- IGAFIT Highlights of Algorithms (HALG), Prag, invited speaker for our paper A solution to Ringel's circle Problem
- Dagstuhl Seminar: Computational Geometry, Schloss Dagstuhl
- Workshop on New Directions in Geometric Algorithms, Utrecht
- Tenth Annual Workshop on Geometry and Graphs, Barbados
- Symposium on Discrete Algorithms (SODA), Florence, speaker for our paper Online Sorting and Translational Packing of Convex Polygons
Teaching
Winter Term 2023/2024
Summer Term 2023
Winter Term 2022/2023
Summer Term 2022
Winter Term 2021/2022
Winter Term 2019/2020
Summer Term 2020
Winter Term 2019/2020
Summer Term 2019
Publications
- On the Connectivity of the Flip Graph of Plane Spanning Paths. [pdf]
with Peter Kramer and Christian Rieck.
accepted at International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2024).
- On the Augmenting Plane Straight-Line Graphs to Meet Parity Constraints. [pdf]
with Aleksander Christiansen, Linda Kleist, Irene Parada, and Eva Rotenberg.
accepted at International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2024).
- Online Sorting and Translational Packing of Convex Polygons [pdf]
with Anders Aamand, Mikkel Abrahamsen and Lorenzo Beretta.
in Proceedings of Symposium on Discrete Algorithms (SODA 2023).
arXiv: 22112.03791.
- A solution to Ringel's problem [pdf] [video]
with James Davies, Chaya Keller, Shakhar Smorodinsky, and Bartosz Walczak.
Journal version accepted at Journal of European Mathematical Society (JEMS).
In Proceedings of 38th Symposium on Computational Geometry (SoCG 2022).
arXiv: 2112.05042.
media attention: [video], [Gil Kalai's blog], [NRC article] [Haaretz article]
- Geometric Embeddability of Complexes is ∃R-complete [pdf]
with Mikkel Abrahamsen and Tillmann Miltzow.
In Proceedings of 39th Symposium on Computational Geometry (SoCG 2023).
arXiv: 2108.02585.
- Complexity of Recognizing Geometric Hypergraphs [pdf]
with Daniel Bertschinger, Nicolas El Maalouly, Tillmann Miltzow, Simon Weber.
Preprint of Extended Abstract appears in the proceedings of 39th European Workshop on Computational Geometry (EuroCG 2023)
In Proceedings of 31st International Symposium on Graph Drawing and Network Visualization.
arXiv: 2302.13597.
- The Complexity of the Hausdorff Distance [pdf]
with Paul Jungeblut and Tillmann Miltzow.
Journal version in Discrete and Computational Geometry (DCG), 2023
In Proceedings of 38th Symposium on Computational Geometry (SoCG 2022).
arXiv: 2112.04343.
- Adjacency Graphs of Polyhedral Surfaces [pdf]
with Elena Arseneva, Boris Klemz, Maarten Löffler, André Schulz, Birgit Vogtenhuber and Alexander Wolff.
Journal version in Discrete and Computational Geometry (DCG), 2023
In Proceedings of 37th Symposium on Computational Geometry (SoCG 2021).
Preprint of Extended Abstract in 36th European Workshop on Computational Geometry (EuroCG 2020)
arXiv: 2103.09803.
- Completeness for the Complexity Class ∀∃ℝ and Area-Universality [pdf]
with Michael G. Dobbins, Tillmann Miltzow, and Pawel Rzazewski.
Journal version in Discrete and Computational Geometry (DCG), 2022.
In Proceedings of WG 2018, LNCS 11159.
arXiv:1712.05142.
- The tripartite-circle crossing number of graphs with two small partition classes [pdf]
with Charles Camacho, Silvia Fernandez-Merchant, Marija Jelic, Rachel Kirsch, Elizabeth Bailey Matson, and Jennifer White.
arXiv: 2108.01032.
- Packing Squares into a Disk with Optimal Worst-Case Density [pdf]
with Sándor P. Fekete, Vijay Gurunathan, Kushagra Juneja, Phillip Keldenich, Christian Scheffer.
Journal version in special issue of Journal of Computational Geometry (JoCG), devoted to selected papers from SoCG 2021.
In Proceedings of 37th Symposium on Computational Geometry (SoCG 2021).
Preprint of Extended Abstract in 36th European Workshop on Computational Geometry (EuroCG 2020) , video talk [video]
arXiv: 2103.07258.
- Training Neural Networks is ER-complete [pdf]
with Mikkel Abrahamsen and Tillmann Miltzow.
In Proceedings of 35th Conference on Neural Information Processing Systems (NeurIPS 2021).
arXiv: 2102.09798.
- Scheduling with Machine Conflicts [pdf]
with Moritz Buchem and Daniel Schmidt genannt Waldschmidt.
In Proceedings of International Workshop on Approximation and Online Algorithms (WAOA 2022).
arXiv: 2102.08231.
- Bounding the tripartite-circle crossing number of complete tripartite graphs [pdf]
with Charles Camacho, Silvia Fernandez-Merchant, Marija Jelic, Rachel Kirsch, Elizabeth Bailey Matson, and Jennifer White.
Journal version in Journal of Graph Theory (JGT), 2022.
In Proceedings of EuroComb 2019 [extended abstract]
Our poster won the Best Poster Award at GD 2018 [poster] [abstract].
arXiv:1910.06963.
- Folding Polyiamonds into Octahedra [pdf]
with Eva Stehr (previously Bolle).
Journal version in Computational Geometry (CGTA), 2022.
In Proceedings of 33rd Canadian Conference on Computational Geometry (CCCG 2021) [pdf].
Preprint of Extended Abstract in 37th European Workshop on Computational Geometry (EuroCG 2021) , [booklet]
- Minimum Scan Cover and Variants -- Theory and Experiments [pdf]
with Kevin Buchin, Sándor Fekete, Alexander Hill, Irina Kostitsyna, Dominik Krupke, Roel Lambers, and Martijn Struijs.
Journal version in ACM Journal of Experimental Algorithmics (JEA), 2022.
In Proceedings of 19th International Symposium on Experimental Algorithms (SEA 2021).
arXiv: 2103.14599.
- Minimum Scan Cover with Angular Transition Costs [pdf]
with Sándor Fekete and Dominik Krupke.
Journal version in Siam Journal on Discrete Mathematics (SIDMA), 2021.
In Proceedings of 36th Symposium on Computational Geometry (SoCG 2020).
arXiv: 2003.08816.
- On Area-Universal Quadrangulations [pdf]
with William Evans, Stefan Felsner, and Stephen Kobourov.
In Journal of Graph Algorithms and Applications (JGAA), 2021.
- Upward Point Set Embeddings of Paths and Trees
with Elena Arseneva, Pilar Cano, Tamara Mchedlidze, Saeed Mehrabi, Irene Parada, Pavel Valtr.
In Proceedings of 15th International Conference and Workshops on Algorithms and Computing (WALCOM 2021).
arXiv: 2012.10525.
- Competitive Location Problems: Balanced Facility Location and the One-Round Manhattan Voronoi Game [pdf]
with Thomas Byrne, Sándor Fekete, Jörg Kalcsics.
In Proceedings of 15th International Conference and Workshops on Algorithms and Computing (WALCOM 2021).
arXiv: 2011.13275.
- Folding Polyominoes with Holes into a Cube [pdf]
with Oswin Aichholzer, Hugo Akitaya, Kenneth C. Cheung, Erik Demaine, Martin Demaine, Sándor Fekete, Irina Kostitsyna, Maarten Löffler, Zuzana Masárová.
Journal Version in Computational Geometry (CGTA), 2020.
In Proceedings of CCCG 2019 [pdf].
arXiv: 1910.09917.
- Rainbow Cycles in Flip Graphs [pdf] [slides]
with Stefan Felsner, Torsten Mütze, and Leon Sering.
Journal version in Siam Journal on Discrete Mathematics (SIDMA), 2020
In Proceedings of 34th Symposium on Computational Geometry (SoCG 2018).
arXiv:1712.07421.
- Targeted Drug Delivery:
Algorithmic Methods for Collecting a Swarm of Particles with Uniform, External Forces. [pdf]
with Aaron T. Becker, Sándor P. Fekete, Li Huang, Phillip Keldenich, Dominik Krupke, Christian Rieck, Arne Schmidt.
In Proceedings of IEEE International Conference on Robotics and Automation (ICRA).
Preprint in Proceedings of 36th European Workshop on Computational Geometry (EuroCG 2020)
- Convexity-Increasing Morphs [pdf]
with Boris Klemz, Anna Lubiw, Lena Schlipf, Frank Staals, Darren Strash.
Journal version in Computational Geometry - Theory and Applications (CGTA), 2019
Conference version WG 2018, LNCS 11159.
arXiv:1802.06579.
- On the Edge-Vertex Ratio of Maximal Thrackles [pdf]
with Oswin Aichholzer, Boris Klemz, Felix Schröder, Birgit Vogtenhuber.
In Proceedings of GD 2019, LNCS 11904.
arXiv:1908.08857.
- Drawing Planar Graphs with Prescribed Face Areas [pdf] [slides]
Journal Version in Journal of Computational Geometry (JoCG) 2018 [pdf].
In Proceedings of WG 2016, LNCS 9941 [pdf].
- On the Area-Universality of Triangulations [pdf]
In Proceedings of GD 2018 , LNCS 11282 [pdf].
arXiv:1808.10864.
- Planar Graphs and Face Areas -- Area-Universality [pdf]
PhD thesis, TU Berlin, 2018
DOI: 10.14279/depositonce-7674
- Upper and Lower Bounds on Long Dual-Paths in Line Arrangements [pdf] [slides]
with Udo Hoffmann and Tillmann Miltzow.
in MFCS 2015 , LNCS 9235
arXiv:1506.03728.
- Unit Contact Representations of Grid Subgraphs with Regular Polytopes in 2D and 3D [pdf] [slides]
with Benjamin Rahman.
In Proceedings of GD 14, LNCS 8871.