[{"language":[{"iso":"eng"}],"_id":"60491","external_id":{"arxiv":["2507.00813"]},"user_id":"91965","department":[{"_id":"100"}],"abstract":[{"lang":"eng","text":"We investigate generalisations of 1-factorisations and hyperfactorisations of the complete graph $K_{2n}$. We show that they are special subsets of the association scheme obtained from the Gelfand pair $(S_{2n},S_2 \\wr S_n)$. This unifies and extends results by Cameron (1976) and gives rise to new existence and non-existence results. Our methods involve working in the group algebra $\\mathbb{C}[S_{2n}]$ and using the representation theory of $S_{2n}$."}],"status":"public","type":"preprint","title":"On the association scheme of perfect matchings and their designs","date_updated":"2025-07-02T07:47:09Z","date_created":"2025-07-02T07:37:23Z","author":[{"first_name":"Lukas-André Dominik","id":"91965","full_name":"Klawuhn, Lukas-André Dominik","orcid":"0009-0009-7736-4885","last_name":"Klawuhn"},{"first_name":"John","full_name":"Bamberg, John","last_name":"Bamberg"}],"year":"2025","citation":{"chicago":"Klawuhn, Lukas-André Dominik, and John Bamberg. “On the Association Scheme of Perfect Matchings and Their Designs,” 2025.","ieee":"L.-A. D. Klawuhn and J. Bamberg, “On the association scheme of perfect matchings and their designs.” 2025.","ama":"Klawuhn L-AD, Bamberg J. On the association scheme of perfect matchings and their designs. Published online 2025.","mla":"Klawuhn, Lukas-André Dominik, and John Bamberg. <i>On the Association Scheme of Perfect Matchings and Their Designs</i>. 2025.","bibtex":"@article{Klawuhn_Bamberg_2025, title={On the association scheme of perfect matchings and their designs}, author={Klawuhn, Lukas-André Dominik and Bamberg, John}, year={2025} }","short":"L.-A.D. Klawuhn, J. Bamberg, (2025).","apa":"Klawuhn, L.-A. D., &#38; Bamberg, J. (2025). <i>On the association scheme of perfect matchings and their designs</i>."}},{"department":[{"_id":"100"}],"user_id":"91965","external_id":{"arxiv":["2510.04675"]},"_id":"61759","language":[{"iso":"eng"}],"type":"preprint","status":"public","abstract":[{"text":"Intersection distribution and non-hitting index are concepts introduced recently by Li and Pott as a new way to view the behaviour of a collection of finite field polynomials. With both an algebraic interpretation via the intersection of a polynomial with a set of lines, and a geometric interpretation via a (q+1)-set possessing an internal nucleus, the concepts have proved their usefulness as a new way to view various long-standing problems, and have applications in areas such as Kakeya sets. In this paper, by exploiting connections with diverse areas including the theory of algebraic curves, cyclotomy and the enumeration of irreducible polynomials, we establish new results and resolve various Open Problems of Li and Pott. We prove geometric results which shed new light on the relationship between intersection distribution and projective equivalence of polynomials, and algebraic results which describe and characterise the degree of Sf - the index of the largest non-zero entry in the intersection distribution of f. We provide new insights into the non-hitting spectrum, and show the limitations of the non-hitting index as a tool for characterisation. Finally, the benefits provided by the connections to other areas are evidenced in two short new proofs of the cubic case. ","lang":"eng"}],"author":[{"first_name":"Lukas-André Dominik","orcid":"0009-0009-7736-4885","last_name":"Klawuhn","full_name":"Klawuhn, Lukas-André Dominik","id":"91965"},{"full_name":"Huczynska, Sophie","last_name":"Huczynska","first_name":"Sophie"},{"full_name":"Paterson, Maura","last_name":"Paterson","first_name":"Maura"}],"date_created":"2025-10-08T14:52:20Z","date_updated":"2025-12-19T11:23:10Z","title":"The Intersection Distribution: New Results and Perspectives","page":"36","citation":{"ama":"Klawuhn L-AD, Huczynska S, Paterson M. The Intersection Distribution: New Results and Perspectives. Published online 2025.","chicago":"Klawuhn, Lukas-André Dominik, Sophie Huczynska, and Maura Paterson. “The Intersection Distribution: New Results and Perspectives,” 2025.","ieee":"L.-A. D. Klawuhn, S. Huczynska, and M. Paterson, “The Intersection Distribution: New Results and Perspectives.” 2025.","apa":"Klawuhn, L.-A. D., Huczynska, S., &#38; Paterson, M. (2025). <i>The Intersection Distribution: New Results and Perspectives</i>.","bibtex":"@article{Klawuhn_Huczynska_Paterson_2025, title={The Intersection Distribution: New Results and Perspectives}, author={Klawuhn, Lukas-André Dominik and Huczynska, Sophie and Paterson, Maura}, year={2025} }","mla":"Klawuhn, Lukas-André Dominik, et al. <i>The Intersection Distribution: New Results and Perspectives</i>. 2025.","short":"L.-A.D. Klawuhn, S. Huczynska, M. Paterson, (2025)."},"year":"2025"},{"abstract":[{"text":"Two fundamental ways to represent a group are as permutations and as matrices. In this paper, we study linear representations of groups that intertwine with a permutation representation. Recently, D'Alconzo and Di Scala investigated how small the matrices in such a linear representation can be. The minimal dimension of such a representation is the \\emph{linear dimension of the group action} and this has applications in cryptography and cryptosystems.\r\n\r\nWe develop the idea of linear dimension from an algebraic point of view by using the theory of permutation modules. We give structural results about representations of minimal dimension and investigate the implications of faithfulness, transitivity and primitivity on the linear dimension. Furthermore, we compute the linear dimension of several classes of finite primitive permutation groups. We also study wreath products, allowing us to determine the linear dimension of imprimitive group actions. Finally, we give the linear dimension of almost simple finite $2$-transitive groups, some of which may be used for further applications in cryptography. Our results also open up many new questions about linear representations of group actions.","lang":"eng"}],"status":"public","type":"preprint","language":[{"iso":"eng"}],"external_id":{"arxiv":["2512.16079"]},"_id":"63384","department":[{"_id":"100"}],"user_id":"91965","year":"2025","citation":{"short":"A. Devillers, M. Giudici, D.R. Hawtin, L.-A.D. Klawuhn, L. Morgan, (2025).","mla":"Devillers, Alice, et al. <i>Linear Dimension of Group Actions</i>. 2025.","bibtex":"@article{Devillers_Giudici_Hawtin_Klawuhn_Morgan_2025, title={Linear dimension of group actions}, author={Devillers, Alice and Giudici, Michael and Hawtin, Daniel R. and Klawuhn, Lukas-André Dominik and Morgan, Luke}, year={2025} }","apa":"Devillers, A., Giudici, M., Hawtin, D. R., Klawuhn, L.-A. D., &#38; Morgan, L. (2025). <i>Linear dimension of group actions</i>.","ama":"Devillers A, Giudici M, Hawtin DR, Klawuhn L-AD, Morgan L. Linear dimension of group actions. Published online 2025.","ieee":"A. Devillers, M. Giudici, D. R. Hawtin, L.-A. D. Klawuhn, and L. Morgan, “Linear dimension of group actions.” 2025.","chicago":"Devillers, Alice, Michael Giudici, Daniel R. Hawtin, Lukas-André Dominik Klawuhn, and Luke Morgan. “Linear Dimension of Group Actions,” 2025."},"title":"Linear dimension of group actions","date_updated":"2025-12-19T11:23:41Z","date_created":"2025-12-19T11:20:46Z","author":[{"first_name":"Alice","full_name":"Devillers, Alice","last_name":"Devillers"},{"last_name":"Giudici","full_name":"Giudici, Michael","first_name":"Michael"},{"full_name":"Hawtin, Daniel R.","last_name":"Hawtin","first_name":"Daniel R."},{"last_name":"Klawuhn","orcid":"0009-0009-7736-4885","id":"91965","full_name":"Klawuhn, Lukas-André Dominik","first_name":"Lukas-André Dominik"},{"full_name":"Morgan, Luke","last_name":"Morgan","first_name":"Luke"}]},{"date_created":"2024-10-08T13:14:45Z","author":[{"first_name":"Lukas-André Dominik","full_name":"Klawuhn, Lukas-André Dominik","id":"91965","orcid":"0009-0009-7736-4885","last_name":"Klawuhn"},{"first_name":"Kai-Uwe","full_name":"Schmidt, Kai-Uwe","last_name":"Schmidt"}],"date_updated":"2024-11-15T12:34:03Z","title":"Transitivity in wreath products with symmetric groups","page":"38","citation":{"ieee":"L.-A. D. Klawuhn and K.-U. Schmidt, “Transitivity in wreath products with symmetric groups,” <i>arXiv:2409.20495</i>. 2024.","chicago":"Klawuhn, Lukas-André Dominik, and Kai-Uwe Schmidt. “Transitivity in Wreath Products with Symmetric Groups.” <i>ArXiv:2409.20495</i>, 2024.","ama":"Klawuhn L-AD, Schmidt K-U. Transitivity in wreath products with symmetric groups. <i>arXiv:240920495</i>. Published online 2024.","apa":"Klawuhn, L.-A. D., &#38; Schmidt, K.-U. (2024). Transitivity in wreath products with symmetric groups. In <i>arXiv:2409.20495</i>.","short":"L.-A.D. Klawuhn, K.-U. Schmidt, ArXiv:2409.20495 (2024).","bibtex":"@article{Klawuhn_Schmidt_2024, title={Transitivity in wreath products with symmetric groups}, journal={arXiv:2409.20495}, author={Klawuhn, Lukas-André Dominik and Schmidt, Kai-Uwe}, year={2024} }","mla":"Klawuhn, Lukas-André Dominik, and Kai-Uwe Schmidt. “Transitivity in Wreath Products with Symmetric Groups.” <i>ArXiv:2409.20495</i>, 2024."},"year":"2024","department":[{"_id":"100"}],"user_id":"91965","external_id":{"arxiv":["2409.20495"]},"_id":"56429","language":[{"iso":"eng"}],"publication":"arXiv:2409.20495","type":"preprint","status":"public","abstract":[{"text":"It is known that the notion of a transitive subgroup of a permutation group\r\n$P$ extends naturally to the subsets of $P$. We study transitive subsets of the\r\nwreath product $G \\wr S_n$, where $G$ is a finite abelian group. This includes\r\nthe hyperoctahedral group for $G=C_2$. We give structural characterisations of\r\ntransitive subsets using the character theory of $G \\wr S_n$ and interpret such\r\nsubsets as designs in the conjugacy class association scheme of $G \\wr S_n$. In\r\nparticular, we prove a generalisation of the Livingstone-Wagner theorem and\r\ngive explicit constructions of transitive sets. Moreover, we establish\r\nconnections to orthogonal polynomials, namely the Charlier polynomials, and use\r\nthem to study codes and designs in $C_r \\wr S_n$. Many of our results extend\r\nresults about the symmetric group $S_n$.","lang":"eng"}]}]