Face monoid actions and tropical hyperplane arrangements, with Mark Kambites.
International Journal of Algebra and Computation 27 (2017), no. 8, 1001-1025.
(Preprint version available at arXiv:1604.03016.)
 The Shortest Identities for Max-Plus Automata with Two States, with Laure Daviaud.
Proc. 42nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2017),
in Leibniz International Proceedings in Informatics (LIPIcs), vol. 83, 48:1-48:13, Kim G. Larsen et. al (eds.), Dagstuhl, Germany, 2017.
 L. G. Kovacs work on Lie powers,
Journal of the Australian Mathematical Society, Volume 102, Issue 1 (2017) pp. 9-19. Special issue dedicated to the memory of Laci Kovacs.
 FP-injectivity of semirings, semigroup rings and Leavitt path algebras, with T. G. Nam,
Communications in Algebra 45 (2017), no. 5, 1893-1906.
 Pure Dimension and Projectivity of Tropical Polytopes, with Zur Izhakian and Mark Kambites.
Advances in Mathematics, 303 (2016), 1236-1263.
(Author accepted manuscript available at arXiv:1106.4525.)
 Idempotent tropical matrices and finite metric spaces, with Mark Kambites,
Advances in Geometry 14 (2014), no. 2, 253-276.
(Preprint version available at arXiv:1203.2480v1.)
 A modular version of Klyachko's theorem on Lie representations of the general linear group,
with R. M. Bryant. Mathematical Proceedings Cambridge Philosophical Society, 153 (2012), 79-98.
(Preprint version available by request.)
 Periodicity of Adams operations on the Green ring of a finite group, with R. M. Bryant.
Journal of Pure and Applied Algebra, 215 (2011), 989-1002.
(Preprint version available at arXiv:0912.2933v1.)
 Free central extensions of groups and modular Lie powers of relation modules, with Ralph Stöhr.
Proceedings of the American Mathematical Society, 138 (2010), 3807-3814.
(Preprint version available by request or via MIMS Eprints:2009.27.)
 Adams operations on the Green ring of a cyclic group of prime-power order, with R. M. Bryant.
Journal of Algebra, 323 (2010), no. 10, 2818-2833.
(Preprint version available at arXiv:0912.1524v1.)
 Free centre-by-nilpotent-by-abelian groups, with Ralph Stöhr,
Bulletin of the London Mathematical Society, 41 (2009), no. 5, 795-803.
(Preprint version available by request or via MIMS Eprints:2008.51.)
 Standard tableaux and Klyachko's Theorem on Lie representations,
Journal of Combinatorial Theory, Series A, 114 (2007), no. 1, 151-158.
(Preprint version available at MIMS Eprints:2005.52.)
 Identities in Upper Triangular Tropical Matrix Semigroups and the Bicyclic Monoid, with Laure Daviaud and Mark Kambites.
Journal of Algebra, to appear.
(Preprint version available at arXiv:1612.04219.)
 Tropical matrix groups, with Zur Izhakian and Mark Kambites.
Semigroup Forum, to appear.
 Linear isomorphisms preserving Green's relations for matrices over semirings, with Alexander Guterman and Mark Kambites.
(Preprint available at arXiv:1709.05277.)
 NP-completeness in the gossip monoid, with Peter Fenner and Mark Kambites.
(Preprint available at arXiv:1606.01026.)
On group actions on free Lie algebras, PhD thesis, Manchester (2007).
Electronic version available at MIMS Eprints:2008.46.
Using tropical mathematics to model ribosome dynamics, with James Hook.
Mathematics Today, Vol. 51, June 2015, 139-141. (David Broomhead memorial issue.)