Stefan Weltge

Stefan Weltge
Hi! I'm a postdoc at ETH Zürich working in the field of mathematical optimization. Most problems I work on deal with theoretical questions in convex and discrete geometry. Currently, I'm at the Institute for Operations Research in the group of Robert Weismantel. Before, I was in Magdeburg where I received my PhD under the supervision of Volker Kaibel.


  1. Characterizing Polytopes Contained in the 0/1-Cube with Bounded Chvátal-Gomory Rank
    with Yohann Benchetrit, Samuel Fiorini, Tony Huynh
    Mathematics of Operations Research, 2018 journal arXiv version

  2. Lifting Linear Extension Complexity Bounds to the Mixed-Integer Setting
    with Alfonso Cevallos, Rico Zenklusen
    Symposium on Discrete Algorithms (SODA), 2018 conference arXiv version

  3. Strengthening Convex Relaxations of 0/1-Sets Using Boolean Formulas
    with Samuel Fiorini, Tony Huynh
    preprint, 2017 submitted arXiv version

  4. Optimality certificates for convex minimization and Helly numbers
    with Amitabh Basu, Michele Conforti, Gérard Cornuéjols, Robert Weismantel
    Operations Research Letters, 2017 journal arXiv version

  5. Extension complexities of Cartesian products involving a pyramid
    with Hans Raj Tiwary, Rico Zenklusen
    Information Processing Letters, 128, 11-13, 2017 journal arXiv version

  6. Tight bounds on discrete quantitative Helly numbers
    with Gennadiy Averkov, Bernardo González Merino, Ingo Paschke, Matthias Schymura
    Advances in Applied Mathematics, 89, 76-101, 2017 journal arXiv version

  7. Notions of Maximality for Integral Lattice-Free Polyhedra: The Case of Dimension Three
    with Gennadiy Averkov, Jan Krümpelmann
    Mathematics of Operations Research, 2017 journal arXiv version

  8. Maximum Semidefinite and Linear Extension Complexity of Families of Polytopes
    with Gennadiy Averkov, Volker Kaibel
    Mathematical Programming Series A, 2017 journal arXiv version

  9. Three Enhancements for Optimization-Based Bound Tightening
    with Ambros M. Gleixner, Timo Berthold, Benjamin Müller
    Journal of Global Optimization, 67 (4), 731-757, 2017 journal

  10. Extended Formulations for Independence Polytopes of Regular Matroids
    with Volker Kaibel, Jon Lee, Matthias Walter
    Graphs and Combinatorics, 32 (5), 1931-1944, 2016 journal arXiv version

  11. Sizes of Linear Descriptions in Combinatorial Optimization
    Dissertation, Otto-von-Guericke-Universität Magdeburg, 2016 thesis
    (winner of the Dissertation Award 2016, Otto-von-Guericke Universität Magdeburg)

  12. Subgraph polytopes and independence polytopes of count matroids
    with Michele Conforti, Volker Kaibel, Matthias Walter
    Operations Research Letters, 43 (5), 457-460, 2015 journal arXiv version

  13. Lower Bounds on the Sizes of Integer Programs without Additional Variables
    with Volker Kaibel
    Mathematical Programming Series B, 154 (1-2), 407-425, 2015 journal arXiv version

  14. Hidden Vertices in Extensions of Polytopes
    with Kanstantsin Pashkovich
    Operations Research Letters, 43 (2), 161-164, 2015 journal arXiv version

  15. A Short Proof that the Extension Complexity of the Correlation Polytope Grows Exponentially
    with Volker Kaibel
    Discrete & Computational Geometry, 53 (2), 396-401, 2015 journal arXiv version

  16. Computing The Extension Complexities of All 4-Dimensional 0/1-Polytopes
    with Michael Oelze, Arnaud Vandaele
    2014 tech report arXiv version

  17. Erweiterte Formulierungen für das Alternaeder
    Diploma Thesis, Otto-von-Guericke-Universität Magdeburg, 2012 thesis