5 papers
Anzahl theorems for trivially intersecting subspaces generating a non-singular subspace I: symplectic and hermitian forms
Maarten De Boeck, Geertrui Van de Voorde
In this paper, we solve a classical counting problem for non-degenerate forms of symplectic and hermitian type defined on a vector space: given a subspace , we find the number o…
Triangle-free graphs with diameter 2
Alice Devillers, Nina Kamčev, Brendan McKay +5
There are finitely many graphs with diameter and girth 5. What if the girth 5 assumption is relaxed? Apart from stars, are there finitely many triangle-free graphs with diamete…
Upper bounds for the number of substructures in finite geometries from the container method
Sam Mattheus, Geertrui Van de Voorde
We use techniques from algebraic and extremal combinatorics to derive upper bounds on the number of independent sets in several (hyper)graphs arising from finite geometry. In this…
Characterising ovoidal cones by their intersection numbers
Bart De Bruyn, Geertrui Van de Voorde
In this paper, we characterise ovoidal cones by their intersection numbers. We first show that a set of points of which intersects planes in , or …
A note on strong blocking sets and higgledy-piggledy sets of lines
Stefano Lia, Geertrui Van de Voorde
This paper studies {\em strong blocking sets} in the -dimensional finite projective space . We first show that certain unions of blocking sets cannot form stro…