On triangles in derangement graphs

K Meagher, AS Razafimahatratra, P Spiga - Journal of Combinatorial …, 2021 - Elsevier
Given a permutation group G, the derangement graph Γ G of G is the Cayley graph with
connection set the set of all derangements of G. We prove that, when G is transitive of …

Cliques in derangement graphs for innately transitive groups

M Fusari, A Previtali, P Spiga - Journal of Group Theory, 2024 - degruyter.com
Given a permutation group 𝐺, the derangement graph of 𝐺 is the Cayley graph with
connection set the derangements of 𝐺. The group 𝐺 is said to be innately transitive if 𝐺 has a …

[HTML][HTML] All 2-transitive groups have the EKR-module property

K Meagher, P Sin - Journal of Combinatorial Theory, Series A, 2021 - Elsevier
We prove that every 2-transitive group has a property called the EKR-module property. This
property gives a characterization of the maximum intersecting sets of permutations in the …

On multipartite derangement graphs

AS Razafimahatratra - arxiv preprint arxiv:2102.05250, 2021 - arxiv.org
Given a finite transitive permutation group $ G\leq\operatorname {Sym}(\Omega) $, with
$|\Omega|\geq 2$, the derangement graph $\Gamma_G $ of $ G $ is the Cayley graph …

Cameron-Liebler sets in permutation groups

J D'haeseleer, K Meagher, VRT Pantangi - arxiv preprint arxiv …, 2023 - arxiv.org
Consider a group $ G $ acting on a set $\Omega $, 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 …

Intersection theorems for finite general linear groups

A Ernst, KU Schmidt - Mathematical Proceedings of the Cambridge …, 2023 - cambridge.org
A subset Y of the general linear group is called t-intersecting if for all, or equivalently x and y
agree pointwise on a t-dimensional subspace of for all. We show that, if n is sufficiently large …

[PDF][PDF] Some Erdös-Ko-Rado results for linear and affine groups of degree two.

K Meagher, AS Razafimahatratra - Art Discret. Appl. Math., 2022 - researchgate.net
In this paper, we show that both the general linear group GL (2, q) and the special linear
group SL (2, q) have both the EKR property and the EKR-module property. This is done …

On the intersection density of primitive groups of degree a product of two odd primes

AS Razafimahatratra - Journal of Combinatorial Theory, Series A, 2023 - Elsevier
A subset F of a finite transitive group G≤ Sym (Ω) is intersecting if for any g, h∈ F there
exists ω∈ Ω such that ω g= ω h. The intersection density ρ (G) of G is the maximum of {| F|| G …

[HTML][HTML] Intersection density of imprimitive groups of degree pq

A Behajaina, R Maleki, AS Razafimahatratra - Journal of Combinatorial …, 2024 - Elsevier
A subset F of a finite transitive group G≤ Sym (Ω) is intersecting if any two elements of F
agree on an element of Ω. The intersection density of G is the number ρ (G)= max⁡{| F|/| G …

[HTML][HTML] The intersection density of non-quasiprimitive groups of degree 3p

R Maleki, AS Razafimahatratra - Discrete Mathematics, 2025 - Elsevier
The intersection density of a finite transitive group G≤ Sym (Ω) is the rational number ρ (G)
given by the ratio between the maximum size of a subset of G in which any two permutations …