Barnabás Janzer

I am a Junior Research Fellow in Mathematics at Magdalen College of the University of Oxford, studying Combinatorics. My research interests include extremal problems (for graphs and set systems) and Ramsey theory. I have previously worked as a postdoc with Benny Sudakov at ETH Zürich, and with Richard Montgomery at the University of Warwick. I completed my PhD (in 2023) at Cambridge, where my supervisor was Imre Leader.

My e-mail address is barnabas.janzer [at] magd [dot] ox [dot] ac [dot] uk. Below is a list of my publications.

• Extending Thomassen's conjecture to directed graphs, with M. Christoph, K. Petrova and R. Steiner
  submitted

• Packing the largest trees in the tree packing conjecture, with R. Montgomery
  J. Eur. Math. Soc., to appear

• Sunflowers and Ramsey problems with restricted intersections, with Z. Jin, B. Sudakov and K. Wu
  Combinatorica 46 (2026), 29

• Ordered Ramsey numbers of powers of paths, with A. Girão and O. Janzer
  Combinatorica 46 (2026), 27

• Chromatic number and regular subgraphs, with R. Steiner and B. Sudakov
  Bull. Lond. Math. Soc. 58 (2026), e70262

• Tight bounds for intersection-reverse sequences, edge-ordered graphs and applications, with O. Janzer, A. Methuku and G. Tardos
  J. Lond. Math. Soc. 112 (2025), e70324

• Rotation inside convex Kakeya sets
  Discrete Comput. Geom. 73 (2025), 149–176

• Tight general bounds for the extremal numbers of 0–1 matrices, with O. Janzer, V. Magnan and A. Methuku
  Int. Math. Res. Not. 2024(15) (2024), 11455–11463

• On locally rainbow colourings, with O. Janzer
  J. Comb. Theory Ser. B 169 (2024), 134–149

• Long running times for hypergraph bootstrap percolation, with A. Espuny Díaz, G. Kronenberg and J. Lada
  Eur. J. Comb. 115 (2024), 103783

• Partial shuffles by lazy swaps, with J. R. Johnson and I. Leader
  SIAM J. Discrete Math. 37 (2023), 2544–2557

• A note on saturation for k-wise intersecting families
  Comb. Theory 2 (2022), #11

• The generalised rainbow Turán problem for cycles
  SIAM J. Discrete Math. 36 (2022), 436–448

• On Query-efficient Planning in MDPs under Linear Realizability of the Optimal State-value Function, with G. Weisz, P. Amortila, Y. Abbasi-Yadkori, N. Jiang and Cs. Szepesvári
  COLT 2021

• Large hypergraphs without tight cycles
  Comb. Theory 1 (2021), #12

• A note on the orientation covering number
  Discrete Appl. Math. 304 (2021), 349–351

• Generalizations of the Ruzsa–Szemerédi and rainbow Turán problems for cliques, with W. T. Gowers
  Comb. Probab. Comput. 30 (2021), 591–608

• Projections of antichains
  Electron. J. Comb. 27 (2020), P1.54

• A note on antichains in the continuous cube
  Mathematika 66 (2020), 514–516

• A new upper bound for cancellative pairs
  Electron. J. Comb. 25 (2018), P2.13