J. D'haeseleer

activity

20182026

most citedCameron-Liebler line classes in AG(3,q)

8 citations · 22 across the 19 of their papers we have counts for

collaborators

24 papers

math.CO2026

Chromatic Number of Grassmann Graphs and MRD codes

Jozefien D'haeseleer, Francesco Pavese, Paolo Santonastaso +1

In this paper we investigate the chromatic number of the Grassmann graphs and of their powers, denoted $J_{q} (n, m, t)$ . In this graph, the vertices correspond to the $m$ -dimensional s…

math.CO2025

Generalized Hamming weights of additive codes and geometric counterparts

Jozefien D'haeseleer, Sascha Kurz

We consider the geometric problem of determining the maximum number $n_{q} (r, h, f; s)$ of $(h - 1)$ -spaces in the projective space $PG (r - 1, q)$ such that each subspace of c…

math.CO2025

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…

math.CO2025

On the Chromatic Number of Grassmann Graphs

Jozefien D'haeseleer, Vladislav Taranchuk

In this paper we study the chromatic number of the Grassmann graphs $J_{q} (n, m)$ . We show that $(1 n - m + 1)_{q} \leq χ (J_{q} (n, m)) \leq (1 n)_{q}$ , which is analogous to the…

math.CO2025

Cameron-Liebler sets of generators in the Klein quadric $Q^{+} (5, q)$

Jozefien D'haeseleer, Jonathan Mannaert, Leo Storme

We investigate Cameron-Liebler sets of planes in the Klein quadric $Q^{+} (5, q)$ in PG $(5, q)$ . We prove that there are many examples of such Cameron-Liebler sets of planes in the Klei…

math.CO2024

A common generalization of hypercube partitions and ovoids in polar spaces

Jozefien D'haeseleer, Ferdinand Ihringer, Kai-Uwe Schmidt

We investigate what we call generalized ovoids, that is families of totally isotropic subspaces of finite classical polar spaces such that each maximal totally isotropic subspace c…

math.CO2023

Regular ovoids and Cameron-Liebler sets of generators in polar spaces

Maarten De Boeck, Jozefien D'haeseleer, Morgan Rodgers

Cameron-Liebler sets of generators in polar spaces were introduced a few years ago as natural generalisations of the Cameron-Liebler sets of subspaces in projective spaces. In this…

math.CO2023

Cameron-Liebler sets in permutation groups

Jozefien D'haeseleer, Karen Meagher, Venkata Raghu Tej Pantangi

Consider a group $G$ acting on a set $Ω$ , the vector $v_{a, b}$ is a vector with the entries indexed by the elements of $G$ , and the $g$ -entry is 1 if $g$ maps $a$ to $b$ , and zero…

math.CO2023

Cospectral mates for generalized Johnson and Grassmann graphs

Aida Abiad, Jozefien D'haeseleer, Willem H. Haemers +1

We provide three infinite families of graphs in the Johnson and Grassmann schemes that are not uniquely determined by their spectrum. We do so by constructing graphs that are cospe…

math.CO2023

Blocking sets, minimal codes and trifferent codes

Anurag Bishnoi, Jozefien D'haeseleer, Dion Gijswijt +1

We prove new upper bounds on the smallest size of affine blocking sets, that is, sets of points in a finite affine space that intersect every affine subspace of a fixed codimension…

math.CO2022

A higgledy-piggledy set of planes based on the ABB-representation of linear sets

Lins Denaux, Jozefien D'haeseleer, Geertrui Van de Voorde

In this paper, we investigate the André/Bruck-Bose representation of certain $F_{q}$ -linear sets contained in a line of $PG (2, q^{t})$ . We show that scattered $\mathbb{F…

math.CO2022

On the Chromatic Number of some generalized Kneser Graphs

Jozefien D'haeseleer, Klaus Metsch, Daniel Werner

We determine the chromatic number of the Kneser graph qΓ_{7,{3,4}} of flags of vectorial type {3, 4} of a rank 7 vector space over the finite field GF(q) for large q and describe t…

math.CO2022★ 3 cited

Degree 2 Boolean Functions on Grassmann Graphs

Jan De Beule, Jozefien D'haeseleer, Ferdinand Ihringer +1

We investigate the existence of Boolean degree $d$ functions on the Grassmann graph of $k$ -spaces in the vector space $F_{q}^{n}$ . For $d = 1$ several non-existence and classifi…

math.CO2020

On the sunflower bound for $k$ -spaces, pairwise intersecting in a point

Aart Blokhuis, Maarten De Boeck, Jozefien D'haeseleer

A $t$ -intersecting constant dimension subspace code $C$ is a set of $k$ -dimensional subspaces in a projective space PG(n,q), where distinct subspaces intersect in a $t$ -dimensional…

math.CO2020★ 1 cited

Hilton-Milner results in projective and affine spaces

Jozefien D'haeseleer

In this article, we analyse maximal sets of $k$ -spaces, in PG(n,q) and AG(n,q), $n > 2 k + t + 2$ , that pairwise meet in at least a $t$ -space. It is known that for both PG(n,q) and AG(n,q…

math.CO2020

Neumaier graphs with few eigenvalues

Aida Abiad, Bart De Bruyn, Jozefien D'haeseleer +1

A Neumaier graph is a non-complete edge-regular graph containing a regular clique. In this paper we give some sufficient and necessary conditions for a Neumaier graph to be strongl…

math.CO2020★ 2 cited

On the chromatic number of two generalized Kneser graphs

Jozefien D'haeseleer, Klaus Metsch, Daniel Werner

We determine the chromatic number of some graphs of flags in buildings of type $A_{4}$ , namely of the Kneser graphs of flags of type ${2, 4}$ in the vector spaces $GF (q)^{5}$ for $q\g…

math.CO2020

On absolute points of correlations in PG $(2, q^{n})$

Jozefien D'haeseleer, Nicola Durante

Let $V$ be a $(d + 1)$ -dimensional vector space over a field $F$ . Sesquilinear forms over $V$ have been largely studied when they are reflexive and hence give rise to a (pos…

math.CO2020

Maximal sets of $k$ -spaces pairwise intersecting in at least a $(k - 2)$ -space

Jozefien D'haeseleer, Giovanni Longobardi, Ago-Erik Riet +1

In this paper, we analyze the structure of maximal sets of $k$ -dimensional spaces in $PG (n, q)$ pairwise intersecting in at least a $(k - 2)$ -dimensional space, for $3 \leq k…

math.CO2020★ 4 cited

Cameron-Liebler $k$ -sets in $AG (n, q)$

Jozefien D'haeseleer, Ferdinand Ihringer, Jonathan Mannaert +1

We study Cameron-Liebler $k$ -sets in the affine geometry, so sets of $k$ -spaces in $AG (n, q)$ . This generalizes research on Cameron-Liebler $k$ -sets in the projective geomet…

math.CO2020★ 8 cited

Cameron-Liebler line classes in AG(3,q)

Jozefien D'haeseleer, Jonathan Mannaert, Leo Storme +1

The study of Cameron-Liebler line classes in PG( $3, q$ ) arose from classifying specific collineation subgroups of PG( $3, q$ ). Recently, these line classes were considered in new sett…

math.CO2019

Translation hyperovals and $F_{2}$ -linear sets of pseudoregulus type

Jozefien D'haeseleer, Geertrui Van de Voorde

In this paper, we study translation hyperovals in PG $(2, q^{k})$ . The main result of this paper characterises the point sets defined by translation hyperovals in the André/Bruck-Bose…

math.CO2019

Equivalent definitions for (degree one) Cameron-Liebler classes of generators in finite classical polar spaces

Jozefien D'haeseleer, Maarten De Boeck

In this article, we study degree one Cameron-Liebler sets of generators in all finite classical polar spaces, which is a particular type of a Cameron-Liebler set of generators in t…

math.CO2018★ 4 cited

Cameron-Liebler sets of k-spaces in PG(n,q)

Aart Blokhuis, Maarten De Boeck, Jozefien D'haeseleer

Cameron-Liebler sets of k-spaces were introduced recently by Y. Filmus and F. Ihringer. We list several equivalent definitions for these Cameron-Liebler sets, by making a generaliz…

Chromatic Number of Grassmann Graphs and MRD codes

Generalized Hamming weights of additive codes and geometric counterparts

A note on the classification of classical distance-regular graphs of negative type and the non-existence of hemisystems

On the Chromatic Number of Grassmann Graphs

Cameron-Liebler sets of generators in the Klein quadric Q+(5,q)

A common generalization of hypercube partitions and ovoids in polar spaces

Regular ovoids and Cameron-Liebler sets of generators in polar spaces

Cameron-Liebler sets in permutation groups

Cospectral mates for generalized Johnson and Grassmann graphs

Blocking sets, minimal codes and trifferent codes

A higgledy-piggledy set of planes based on the ABB-representation of linear sets

On the Chromatic Number of some generalized Kneser Graphs

Degree 2 Boolean Functions on Grassmann Graphs

On the sunflower bound for k-spaces, pairwise intersecting in a point

Hilton-Milner results in projective and affine spaces

Neumaier graphs with few eigenvalues

On the chromatic number of two generalized Kneser graphs

On absolute points of correlations in PG(2,qn)

Maximal sets of k-spaces pairwise intersecting in at least a (k−2)-space

Cameron-Liebler k-sets in AG(n,q)

Cameron-Liebler line classes in AG(3,q)

Translation hyperovals and F2​-linear sets of pseudoregulus type

Equivalent definitions for (degree one) Cameron-Liebler classes of generators in finite classical polar spaces

Cameron-Liebler sets of k-spaces in PG(n,q)

Cameron-Liebler sets of generators in the Klein quadric $Q^{+} (5, q)$

On the sunflower bound for $k$ -spaces, pairwise intersecting in a point

On absolute points of correlations in PG $(2, q^{n})$

Maximal sets of $k$ -spaces pairwise intersecting in at least a $(k - 2)$ -space

Cameron-Liebler $k$ -sets in $AG (n, q)$

Translation hyperovals and $F_{2}$ -linear sets of pseudoregulus type