Oliver Janzer

I am a Junior Research Fellow at Trinity College, Cambridge. Previously, I was an ETH Zürich Postdoctoral Fellow working with Benny Sudakov. I did my PhD between 2017 and 2020 at the University of Cambridge under the supervision of Timothy Gowers. My main research interests are Extremal and Probabilistic Graph Theory, Ramsey Theory and Additive Combinatorics. My e-mail address is oj224 at cam dot ac dot uk

From January 2025, I will be a tenure-track Assistant Professor at EPFL, where I will have funding for PhD students and postdocs. If you are interested in such positions, feel free to contact me at the email address above. You may apply for a postdoc position in my group at this link.

Here is my CV. You can find my papers below with links to their arXiv versions.

• Edge-disjoint cycles with the same vertex set, with D. Chakraborti, A. Methuku and R. Montgomery
  submitted

• Tight general bounds for the extremal numbers of 0-1 matrices, with Barnabas Janzer, V. Magnan and A. Methuku
  Int. Math. Res. Not. IMRN, to appear

• Ordered Ramsey numbers of powers of paths, with A. Girao and Barnabas Janzer
  submitted

• Power saving for the Brown-Erdős-Sós problem, with A. Methuku, A. Milojevic and B. Sudakov
  submitted

• On the generalized Turán problem for odd cycles, with Cs. Beke
  SIAM J. Discrete Math., to appear

• Improved bounds for the Erdős-Rogers (s,s+2)-problem, with B. Sudakov
  submitted

• On MaxCut and the Lovasz theta function, with I. Balla and B. Sudakov
  Proceedings of the American Mathematical Society, to appear

• On locally rainbow colourings, with Barnabas Janzer
  Journal of Combinatorial Theory, Series B, to appear

• Extremal number of graphs from geometric shapes, with J. Gao, H. Liu and Z. Xu
  Israel Journal of Mathematics, to appear

• On the Turán number of the hypercube, with B. Sudakov
  Forum of Mathematics, Sigma, to appear

• Regular subgraphs of linear hypergraphs, with B. Sudakov and I. Tomon
  submitted

• Small subgraphs with large average degree, with B. Sudakov and I. Tomon
  Combinatorica, to appear

• Resolution of the Erdős-Sauer problem on regular subgraphs, with B. Sudakov
  Forum of Mathematics, Pi (2023), Vol. 11: e19

• Asymptotics of the hypergraph bipartite Turán problem, with D. Bradac, L. Gishboliner and B. Sudakov
  Combinatorica 43 (2023): 429-446

• The Turán number of the grid, with D. Bradac, B. Sudakov and I. Tomon
  Bull. London Math. Soc. 55 (2023), 194-204

• Rational exponents near two, with D. Conlon
  Advances in Combinatorics, 2022:9, 10pp

• Tiling with monochromatic bipartite graphs of bounded maximum degree, with A. Girao
  submitted

• Disproof of a conjecture of Erdős and Simonovits on the Turán number of graphs with minimum degree 3
  Int. Math. Res. Not. IMRN, Volume 2023, Issue 10, May 2023, Pages 8478–8494 

• Counting H-free orientations of graphs, with M. Bucic and B. Sudakov
  Math. Proc. Camb. Phil. Soc. (2023), 174, 79-95

• New results for MaxCut in H-free graphs, with S. Glock and B. Sudakov
  Journal of the London Mathematical Society 2023;108:441-481

• On the Zarankiewicz problem for graphs with bounded VC-dimension, with C. Pohoata
  Combinatorica, to appear

• Coloring linear hypergraphs: the Erdős-Faber-Lovász conjecture and the Combinatorial Nullstellensatz, with Z. L. Nagy
  Designs, Codes and Cryptography (2022) 90:1991-2001

• On the Turán number of the blow-up of the hexagon, with A. Methuku and Z. L. Nagy
  SIAM J. Discrete Math. 36 (2022), 1187-1199

• Rainbow Turán number of even cycles, repeated patterns and blow-ups of cycles
  Israel Journal of Mathematics 253 (2023) , 813-840

• The maximum number of induced C_5's in a planar graph, with D. Ghosh, E. Győri, A. Paulos, N. Salia and O. Zamora
  Journal of Graph Theory, 2022;99:378-398

• The extremal number of the subdivisions of the complete bipartite graph
  SIAM J. Discrete Math. 34 (2020), 241-250

• The extremal number of longer subdivisions
  Bull. London Math. Soc. 53 (2021), 108-118

• The Turán number of blow-ups of trees, with A. Grzesik and Z. L. Nagy
  Journal of Combinatorial Theory, Series B 156 (2022), 299-309

• More on the extremal number of subdivisions, with D. Conlon and J. Lee
  Combinatorica 41 (2021), 465-494

• Polynomial bound for the partition rank vs the analytic rank of tensors
  Discrete Analysis 2020:7, 18 pp

• Subsets of Cayley graphs that induce many edges, with W. T. Gowers
  Theory of Computing 15(20), 2019, 1-29

• Improved bounds for the extremal number of subdivisions
  The Electronic Journal of Combinatorics 26 (2019), P3.3

• Improved bounds for the Erdős-Rogers function, with W. T. Gowers
  Advances in Combinatorics, 2020:3, 27 pp

Unpublished manuscripts

• Long directed paths in Eulerian digraphs, with B. Sudakov and I. Tomon

• Low analytic rank implies low partition rank for tensors