J. Schillewaert

activity

20092026

most citedOn exceptional Lie geometries

5 citations · 9 across the 22 of their papers we have counts for

collaborators

31 papers

math.GR2026

Resolutions of orbifold generalised triangle groups

Sean P. Carroll, Thomas Csizmadia, Jeroen Schillewaert

Let $T = ⟨ f, g ∣ f^{l} = g^{m} = W^{n} = 1 ⟩$ be a generalised triangle group in which $W$ is the Farey word of a rational slope $q = r / s$ , and suppose that $T$ is the fundament…

math.GR2025

On Wiegold's conjecture for the small Ree groups

Sira Busch, Mark Pengitore, Jeroen Schillewaert +1

The Wiegold conjecture holds for the small Ree groups for $k$ -tuples where $k \geq 5$ .

math.GR2024★ 1 cited

Groups of Projectivities and Levi Subgroups in Spherical Buildings of Simply Laced Type

Sira Busch, Jeroen Schillewaert, Hendrik Van Maldeghem

We introduce the special and general projectivity groups attached to a simplex $F$ of a thick irreducible spherical building of simply laced type. If the residue of $F$ is irreduci…

math.GR2023

Basic Non-Archimedean Jørgensen Theory

Matthew Conder, Harris Pok Hei Leung, Jeroen Schillewaert

We prove a non-archimedean analogue of Jørgensen's inequality, and use it to deduce several algebraic convergence results. As an application we show that every dense subgroup of $\…

math.GR2022

Distances between fixed-point sets in 2-dimensional Euclidean buildings are realised

Harris Leung, Jeroen Schillewaert, Anne Thomas

We prove that if two finitely generated groups act on a metrically complete 2-dimensional Euclidean building, then the distance between their fixed-point sets is realised. Our proo…

math.GR2022

Discrete two-generator subgroups of $PS L_{2}$ over non-archimedean local fields

Matthew J. Conder, Jeroen Schillewaert

Let $K$ be a non-archimedean local field with residue field of characteristic $p$ . We give necessary and sufficient conditions for a two-generator subgroup $G$ of $PS L_{2} (K)$ …

math.GT2022

Concrete one complex dimensional moduli spaces of hyperbolic manifolds and orbifolds

Alex Elzenaar, Gaven Martin, Jeroen Schillewaert

The Riley slice is arguably the simplest example of a moduli space of Kleinian groups; it is naturally embedded in $C$ , and has a natural coordinate system (introduced b…

math.GT2022

The combinatorics of Farey words and their traces

Alex Elzenaar, Gaven Martin, Jeroen Schillewaert

We introduce a family of 3-variable "Farey polynomials" that are closely connected with the geometry and topology of $3$ -manifolds and orbifolds as they can be used to produce conc…

cs.RO2021

Concurrent Transmission for Multi-Robot Coordination

Sourabha Bharadwaj, Karunakar Gonabattula, Sudipta Saha +2

An efficient communication mechanism forms the backbone for any multi-robot system to achieve fruitful collaboration and coordination. Limitation in the existing asynchronous trans…

math.CO2021

Characterising elliptic and hyperbolic hyperplanes of the parabolic quadric \Q(2n,q)

Jeroen Schillewaert, Geertrui Van de Voorde

We provide a natural characterisation for the sets of elliptic and hyperbolic hyperplanes of the parabolic quadric Q(2n,q) when q is even. This characterisation is based on the num…

math.GT2021

Approximations of the Riley slice

Alex Elzenaar, Gaven Martin, Jeroen Schillewaert

Adapting the ideas of L. Keen and C. Series used in their study of the Riley slice of Schottky groups generated by two parabolics, we explicitly identify `half-space' neighbourhood…

math.CO2021

Quasi-polar spaces

Jeroen Schillewaert, Geertrui Van de Voorde

Quasi-polar spaces are sets of points having the same intersection numbers with respect to hyperplanes as classical polar spaces. Non-classical examples of quasi-quadrics have been…

math.GR2021★ 1 cited

A strong Schottky lemma on $n$ generators for $CAT (0)$ spaces

Matthew J. Conder, Jeroen Schillewaert

We give a criterion for a set of $n$ hyperbolic isometries of a $CAT (0)$ metric space $X$ to generate a free group on $n$ generators. This extends a result by Alperin, Far…

math.CO2020★ 5 cited

On exceptional Lie geometries

Anneleen De Schepper, Jeroen Schillewaert, Hendrik Van Maldeghem +1

Parapolar spaces are point-line geometries introduced as a geometric approach to (exceptional) algebraic groups. We characterize a wide class of Lie geometries as parapolar spaces…

math.GR2020

Constructing highly regular expanders from hyperbolic Coxeter groups

Marston Conder, Alexander Lubotzky, Jeroen Schillewaert +1

A graph $X$ is defined inductively to be $(a_{0}, \dots, a_{n - 1})$ -regular if $X$ is $a_{0}$ -regular and for every vertex $v$ of $X$ , the sphere of radius $1$ around $v$ is an $(a_1,\dot…

math.GR2020★ 1 cited

Fixed points for group actions on 2-dimensional affine buildings

Jeroen Schillewaert, Koen Struyve, Anne Thomas

We prove a local-to-global result for fixed points of groups acting on affine buildings (possibly non-discrete) of types $A ~_{2}$ or $C ~_{2}$ . In the discrete case, our t…

math.CO2019

Characterising hyperbolic hyperplanes of a non-singular quadric in $P G (4, q)$

S. G. Barwick, Alice M. W. Hui, Wen-Ai Jackson +1

Let $H$ be a non-empty set of hyperplanes in $P G (4, q)$ , $q$ even, such that every point of $P G (4, q)$ lies in either $0$ , $\frac{1}{2} q^{3}$ or $\frac{1}{2} (q^{3} + q^{2})$ hyperplanes of $H$ , and…

math.CO2017

On exceptional compact homogeneous geometries of type C3

Jeroen Schillewaert, Koen Struyve

We provide a uniform framework to study the exceptional homogeneous compact geometries of type C3. This framework is then used to show that these are simply connected, answering a…

math.CO2017

Solution to Bishnoi's conjecture on minimal t-fold blocking sets of maximal size

Jeroen Schillewaert

Bishnoi conjectured that if a minimal t-fold blocking set in a projective plane of prime power order has maximal size then it is either a projective plane minus one point, the comp…

math.CO2017

Minimal multiple blocking sets

Anurag Bishnoi, Sam Mattheus, Jeroen Schillewaert

We prove that a minimal $t$ -fold blocking set in a finite projective plane of order $n$ has cardinality at most \[\frac{1}{2} n\sqrt{4tn - (3t + 1)(t - 1)} + \frac{1}{2} (t - 1)n +…

math.MG2015

Strongly transitive actions on Euclidean buildings

Linus Kramer, Jeroen Schillewaert

We prove a decomposition result for a group $G$ acting strongly transitively on the Tits boundary of a Euclidean building. As an application we provide a local to global result for…

math.AG2014

Severi's theorem for d-uple Veronese varieties

Jeroen Schillewaert, Koen Struyve

We characterize $d$ -uple Veronese embeddings of finite-dimensional projective spaces. The easiest non-trivial instance of our theorem is the embedding of the projective plane in 5-…

math.MG2013

Imbrex geometries

Jeroen Schillewaert, Hendrik Van Maldeghem

We introduce an axiom on strong parapolar spaces of diameter 2, which arises naturally in the framework of Hjelmslev geometries. This way, we characterize the Hjelmslev-Moufang pla…

math.MG2013

Generalised Veroneseans

Andreas Klein, Jeroen Schillewaert, Leo Storme

In \cite{ThasHVM}, a characterization of the finite quadric Veronesean $V_{n}^{2^{n}}$ by means of properties of the set of its tangent spaces is proved. These tangent sp…

Resolutions of orbifold generalised triangle groups

On Wiegold's conjecture for the small Ree groups

Groups of Projectivities and Levi Subgroups in Spherical Buildings of Simply Laced Type

Basic Non-Archimedean Jørgensen Theory

Distances between fixed-point sets in 2-dimensional Euclidean buildings are realised

Discrete two-generator subgroups of PSL2​ over non-archimedean local fields

Concrete one complex dimensional moduli spaces of hyperbolic manifolds and orbifolds

The combinatorics of Farey words and their traces

Concurrent Transmission for Multi-Robot Coordination

Characterising elliptic and hyperbolic hyperplanes of the parabolic quadric \Q(2n,q)

Approximations of the Riley slice

Quasi-polar spaces

A strong Schottky lemma on n generators for CAT(0) spaces

On exceptional Lie geometries

Constructing highly regular expanders from hyperbolic Coxeter groups

Fixed points for group actions on 2-dimensional affine buildings

Characterising hyperbolic hyperplanes of a non-singular quadric in PG(4,q)

On exceptional compact homogeneous geometries of type C3

Solution to Bishnoi's conjecture on minimal t-fold blocking sets of maximal size

Minimal multiple blocking sets

Strongly transitive actions on Euclidean buildings

Severi's theorem for d-uple Veronese varieties

Imbrex geometries

Generalised Veroneseans

Discrete two-generator subgroups of $PS L_{2}$ over non-archimedean local fields

A strong Schottky lemma on $n$ generators for $CAT (0)$ spaces

Characterising hyperbolic hyperplanes of a non-singular quadric in $P G (4, q)$