5 papers · 1 filter
Strongly regular graphs from hyperbolic quadrics and their maximal cliques
Antonio Cossidente, Jan De Beule, Giuseppe Marino +2
Let be a hyperbolic quadric of $\PG(2n+1,q)$. Fix a generator of the quadric. Define $\cG_n$ as the graph with as vertex set the points of $Q^+(2n+1,q)\setminus…
A sporadic strongly regular graph with parameters from a primitive action of the symmetric group on elements
Sam Adriaensen, Robert F. Bailey, Jan De Beule +1
There are up to isomorphism exactly three strongly regular graphs with parameters whose automorphism group acts primitively on the vertices. Two of these graphs be…
A note on the classification of classical distance-regular graphs of negative type and the non-existence of hemisystems
Sam Adriaensen, Jan De Beule, Jozefien D'haeseleer +1
DISCLAIMER: Due to an error in the literature, we cannot be sure that the conclusions drawn in this paper are correct. The goal of this note is to connect some interesting results…
The largest sets of non-opposite chambers in spherical buildings of type
Jan De Beule, Philipp Heering, Sam Mattheus +1
The investigation into large families of non-opposite flags in finite spherical buildings has been a recent addition to a long line of research in extremal combinatorics, extending…
An algebraic approach to ErdÅs-Ko-Rado sets of flags in spherical buildings II
Jan De Beule, Sam Mattheus, Klaus Metsch
We continue our investigation of ErdÅs-Ko-Rado (EKR) sets of flags in spherical buildings. In previous work, we used the theory of buildings and Iwahori-Hecke algebras to obtain u…