Most of my publications are about extremal combinatorics in finite geometries which I often solve with help from algebraic combinatorics. Among other things I am interested in ovoids, spreads, tight sets, EKR sets, MMS sets, some Ramsey numbers, distance-regular graphs, network codes and generalized polygons. I try to have descriptive titles which might be more helpful than my random list of keywords.


Please note that sometimes there are significant differences between the preprint and the journal version of a paper.
  1. With Ryan Bergen, Shaun Fallat, Adam Gorr, Karen Meagher, Alison Purdy, Boting Yang, Guanglong Yu (University of Regina Discrete Mathematics Research Group): Infection in Hypergraphs. Discrete Applied Mathematics, Accepted. Preprint.
  2. With Klaus Metsch and Bernhard Mühlherr: An EKR theorem for finite buildings of type Dl. Journal of Algebraic Combinatorics, Accepted.
  3. With Karen Meagher: Miklós-Manickam-Singhi Conjectures on Partial Geometries. Designs, Codes and Cryptography, Accepted. Preprint.
  4. With Anurag Bishnoi: The non-existence of distance-2 ovoids in H(4)^D. Contributions to Discrete Mathematics, Accepted. Preprint.
  5. With Peter Sin and Qing Xiang: New Bounds for Partial Spreads of H(2d-1, q^2) and Partial Ovoids of the Ree-Tits Octagon. Journal of Combinatorial Theory A, 2017. Preprint.
  6. With Klaus Metsch: Large {0, 1,...,t}-Cliques in Dual Polar Graphs. Journal of Combinatorial Theory A, 2017. Preprint.
  7. A Switching for Strongly Regular Collinearity Graphs From Polar Spaces. Journal of Algebraic Combinatorics, 2017. Preprint.
  8. With John Bamberg and Jan De Beule: New non-existence proofs for ovoids of Hermitian polar spaces and hyperbolic quadrics, Annals of Combinatorics, 2017. Preprint.
  9. A Note on the Manickam-Miklós-Singhi Conjecture for Vector Spaces, European Journal of Combinatorics, 2016. Preprint.
  10. Cross-intersecting Erdős-Ko-Rado Sets in Dual Polar Graphs, Electronic Journal of Combinatorics, 2015.
  11. A new upper bound for constant distance codes of generators on hermitian polar spaces of type H(2d − 1, q^2), Journal of Geometry, 2014. Preprint.
  12. A Characterisation of the Natural Embedding of the Split Cayley Hexagon in PG(6,q) by Intersection Numbers in Finite Projective Spaces of Arbitrary Dimension. Discrete Mathematics, 2014. Preprint.
  13. With Klaus Metsch: On the Maximum Size of Erdős-Ko-Rado Sets in H(2d+1, q^2), Designs, Codes and Cryptography, 2014. Preprint.


Colloquium/Conference Talks

(Please ask for slides of any of my talks if you want them. I stopped uploading most of them.)

Seminar/Invited Session Talks

Contributed Talks


The Hebrew University of Jerusalem and Einstein Institute.

University of Regina and Department of Mathematics and Statistics.

Justus-Liebig-Universität Gießen and Mathematisches Institut.