Mathematics

The p-norms in the 2d-plane, a picture I made on LaTeX for the functional analysis group at Oxford.

Research

Broadly speaking, I am interested in two of the main sub-branches of functional analysis - operator theory and operator algebras. If functional analysis can be considered an intersection between analysis and algebra, then operator theory corresponds to 'more analysis' and operator algebras corresponds to 'more algebra'.

On the operator theory side of things: I work in the asymptotics theory of operator semigroups, both strongly continuous and discrete, and its applications to partial differential equations and dynamical systems.

This means that I look at systems that evolve to an equilibrium through time (continuously or in steps) and use abstract methods to quantify the rate at which this change happens. This can be used, for example, to obtain the rate at which the energy of a system with damping decays to zero.

I am interested in both the development of new asymptotic theory and the application of theory (both new and old) to concrete models and systems.

On the operator algebra side of things: I am involved in various projects to do with C*-algebras. These are operator algebras that have deep connections and applications to quantum physics. In particular, I am working on C*-algebras that encode information from (higher-rank or topological) graphs and groupoids (group-like objects with a partially defined multiplication and multiple identities), the study of which involves operator K-theory.

Papers



2020

[1] 'Optimal energy decay in a one-dimensional wave-heat system with infinite heat part' with David Seifert. Journal of Mathematical Analysis and Applications 482 (2020), 123563; pre-print can be found on arXiv here.

[2] 'Optimal energy decay in a one-dimensional wave-heat-wave system'. Semigroups of operators: theory and applications, ed. by J. Banasiak, A. Bobrowski, M. Lachowicz, and Yu. Tomilov, Springer Proceedings in Mathematics and Statistics, Springer, Cham, 2020; pre-print can be found on arXiv here.

[3] 'Direct integrals of strongly continuous operator semigroups'. Journal of Mathematical Analysis and Applications 489 (2020), 124176; pre-print can be found on arXiv here.

[4] 'Optimal rates of decay in the Katznelson-Tzafriri theorem for operators on Hilbert spaces' with David SeifertJournal of Functional Analysis 279(2020), 108799 ; pre-print can be found on arXiv here.

2021

[5] 'A categorical approach to operator semigroups'. Semigroup Forum 102 (2021) 495-516; pre-print can be found on arXiv here.

2023

[6] 'Stably finite extensions of rank-two graph C*-algebras' with Astrid an Huef and Aidan Sims. Journal of Operator Theory 90 (2023), 263–310; pre-print can be found on arXiv here.

[7] 'Reconstruction of topological graphs and their Hilbert bimodules' with Rodrigo Frausino and Aidan Sims. Proceedings of the Royal Society of Edinburgh Section A: Mathematics (2023; first view); pre-print can be found on  arXiv here.

Pre-prints:

[8] 'A twist over a minimal étale groupoid that is topologically nontrivial over the interior of the isotropy' with Becky Armstrong, Aidan Sims and Yumiao Zhou; pre-print can be found on arXiv here.

Other:

[9] 'Microthesis: Asymptotics of Operator Semigroups and Applications'. London Mathematical Society Newsletter 507 (2023), 34-36.

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