Holger Dell

Selected works

1. The Parameterised Complexity of Counting Small Sub-Hypergraphs

   Marco Bressan, Julian Brinkmann, Holger Dell, Marc Roth, Philip Wellnitz · SODA 2026

2. Solving Polynomial Equations Over Finite Fields

   Holger Dell, Anselm Haak, Melvin Kallmayer, Leo Wennmann · SODA 2025

3. Nearly Optimal Independence Oracle Algorithms for Edge Estimation in Hypergraphs

   Holger Dell, John Lapinskas, Kitty Meeks · ICALP 2024

4. Satisfiability Allows No Nontrivial Sparsification Unless the Polynomial-Time Hierarchy Collapses

   Holger Dell, Dieter van Melkebeek · J. ACM 2014

5. On Problems as Hard as CNF-SAT

   Marek Cygan, Holger Dell, Daniel Lokshtanov, Dániel Marx, Jesper Nederlof, Yoshio Okamoto, Ramamohan Paturi, Saket Saurabh, Magnus Wahlström · ACM Trans. Algorithms 2016

6. Homomorphisms Are a Good Basis for Counting Small Subgraphs

   Radu Curticapean, Holger Dell, Dániel Marx · STOC 2017

The complete list is on DBLP

Research

I design efficient algorithms for discrete problems and prove intractability results. My research focuses on combinatorial counting problems (including approximate counting and sampling), algebraic graph algorithms, and parameterized and fine-grained complexity.

Teaching

I teach in a student-centered way and put an emphasis on carefully crafted exercises and assignments. My approach is inspired by alternative grading methods, particularly the Grading for Growth philosophy. I am working on Algo-Learn, a self-assessment e-learning platform for undergraduate courses in algorithms and data structures, in which exercises are generated and graded programmatically.

Curriculum vitae

1. 2019–Associate ProfessorIT University of Copenhagen
2. 2020–2025ProfessorGoethe University Frankfurt
3. 2015–2016Research FellowSimons Institute, UC Berkeley
4. 2014–2019Independent Research Group LeaderSaarland University
5. 2013–2014PostdocUniversité Paris Diderot
6. 2011–2013PostdocUW–Madison
7. 2011PhD, advised by Martin GroheHumboldt University of Berlin