Dr Jason Semeraro

Lecturer in Mathematics

Programme Director of BSc and MMath Mathematics

jpgs1@leicester.ac.uk

Tel: +44 (0)116 252 3892

Office: College House, 105

About me

I completed my DPhil in 2013 at the University of Oxford under the supervision of David Craven and Michael Collins. From 2013-2019 I was a Heilbronn Fellow, first at the University of Bristol and then at the University of Leicester. My Erdős number is 2.

Research

I am interested in interactions between algebraic topology, group theory, representation theory and combinatorics. Currently I want to develop a homotopical approach to the local-global conjectures in modular representation theory. Here is a paper I wrote with Radha Kessar and Gunter Malle on that subject.

With Chris Parker I have written some code to compute with and classify fusion systems.

I organised a conference on topological methods in group representation theory with Frank Neumann in November 2019

Here is a list of papers:

Weight conjectures for $\ell$-compact groups and spetses arXiv: 2008.07213 (joint with Radha Kessar and Gunter Malle) (submitted)

Algorithms for fusion systems with applications to $p$ -groups of small order arXiv: 2003.01600 (joint with Chris Parker) (submitted)

Weights in a Benson--Solomon block arXiv: 1712.02826 (joint with Justin Lynd) (submitted)

A $2$-compact group as a spets arXiv: 1906.00898 Exper. Math. (to appear)

Weight conjectures for fusion systems Adv. Math. 357 (2019), 1-40 (joint with Radha Kessar, Markus Linckelmann and Justin Lynd)

Fusion systems on maximal class $3$-groups of rank two revisited, Proc. Amer. Math. Soc. 147 (2019), 3773-3786 (joint with Chris Parker)

Fusion systems over a Sylow $p$-subgroup of $G_2(p)$ Math. Z. 289 (2018), 629-662 (joint with Chris Parker)

The cycle polynomial of a permutation group Electron. J. Comb, Volume 25, Issue 1 (2018) (joint with Peter Cameron)

Conway groupoids and completely transitive codes Combinatorica, 38 (2) (2018) 399-442| (joint with Nick Gill and Neil Gillespie)

Reduced fusion systems over $p$-groups with abelian subgroup of index $p$: II Adv. Math 322 (2017), 201-268 (joint with David Craven and Bob Oliver)

Conway’s groupoid and its relatives Contemporary Mathematics Volume 694, 2017 in honour of John H. Conway (joint with Nick Gill, Neil Gillespie and Cheryl Praeger)

Conway groupoids, regular two-graphs and supersimple designs Séminaire Lotharingien de Combinatoire, Issue 79 (2017) (joint with Nick Gill, Neil Gillespie and Cheryl Praeger)

Tournaments, 4-uniform hypergraphs, and an exact extremal result J. Comb. Theory, Series B, 126 (2017) 114-136 (joint with Karen Gunderson)

Generating groups using hypergraphs Quart. J. Math, 67 (1) (2016), 29-52 (joint with Nick Gill, Neil Gillespie and Tony Nixon)

Bounding the number of hyperedges in friendship $r$-hypergraphs European J. Combinatorics 51 (2016), 125-134 (joint with Karen Gunderson and Natasha Morrison)

Centralizers of normal subgroups and the $Z^*$-theorem J. Algebra 439 (2015), 511-514 (joint with Ellen Henke)

Centralizers of subsystems of fusion systems J. Group Theory 18 (2015), 393-405

Trees of fusion systems J. Algebra, 399 (2014), 1051-1072

Recent and upcoming travel

Groups, representations and applications: new perspectives, INI, Cambridge, March 01-14 2020

Groups and Geometries, BIRS, Banff, August 25-30 2019

Classifying spaces of finite groups of Lie type, Copenhagen, July 2019

Representations of Finite Groups, Oberwolfach, March 2019

Group representation theory and applications, MSRI, Berkeley, March 2018

Fun Stuff

Noughts and Crosses
Conway's Cosmological Theorem
M(13) demonstration
Finite simple group of order two
Quiver mutations in Java