Dr Richard Pymar

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Overview
Overview
Biography
I am a Senior Lecturer in the School of Computing and Mathematical Sciences at Birkbeck, University of London. My research is in probability theory, focusing on how systems with many interacting random components behave over time and are influenced by their environment. Key topics include mixing times, interacting particle systems (like exclusion and voter models), and the Parabolic Anderson Model.
I completed my PhD and Master's degrees at the University of Cambridge, where I was based from 2004 to 2011. Afterwards, I held postdoctoral Research Associate positions, first at LAREMA (Université d'Angers, France) and then at University College London from 2013 to 2016. I joined Birkbeck in 2017.
Qualifications
- PhD, University of Cambridge
- MMath, University of Cambridge
- MA, University of Cambridge
Administrative responsibilities
- Undergraduate Education Lead (Mathematics & Statistics)
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Research
Research
Research interests
- Probability Theory
Research overview
My research interests lie within probability theory and stochastic processes, with a primary focus on systems involving interaction between randomly evolving particles. My work centers on several key areas:
- Interacting particle systems: I'm interested in analysing the dynamics and long-time properties of models such as exclusion processes, voter models, and splitting processes defined on finite graphs.
- Mixing times of markov chains: A significant portion of my research involves quantifying the rate of convergence of stochastic processes to equilibrium as a function of the size and geometry of the state space.
- Stochastic processes in random media: I investigate models where processes evolve in a random environment, notably the Parabolic Anderson Model (PAM) and related systems like the Bouchaud-Anderson model with the goal of understanding phenomena such as localisation versus delocalisation driven by the random potential.
An interactive visualisation related to the chameleon process, a tool sometimes employed in this research, is available at: https://richardpymar.github.io/
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Supervision and teaching
Supervision and teaching
Supervision
I welcome enquiries from prospective PhD students who are interested in undertaking research in any of my areas of research interest.
Teaching
I teach on the MSc in Applied Statistics (modules Probability and Stochastic Modelling, Statistical Analysis) and the BSc in Mathematics (module Data Skills).
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Publications
Publications
Article
- Pymar, Richard and Rivera, N. (2024) Asymptomatic behaviour of the noisy voter model density process. The Annals of Applied Probability 34 (5), pp. 4554-4594. ISSN 1050-5164.
- Pymar, Richard and Rivera, N. (2024) Mixing of the symmetric beta-binomial splitting process on arbitrary graphs. Annales de l'Institut Henri Poincare (B) Probability and Statistics ISSN 0246-0203. (In Press)
- Harris, C. and Pymar, Richard and Rowat, Colin (2022) Joint Shapley Values: a measure of joint feature importance. International Conference on Learning Representations
- Pymar, Richard and Hermon, J. (2020) The exclusion process mixes (almost) faster than independent particles. Annals of Probability 48 (6), pp. 3077-3123. ISSN 0091-1798.
- Muirhead, S. and Pymar, Richard and Sidorova, N. (2019) A new phase transition in the parabolic Anderson model with partially duplicated potential. Stochastic Processes and their Applications 129 (11), pp. 4704-4746. ISSN 0304-4149.
- Connor, S.B. and Pymar, Richard (2019) Mixing times for exclusion processes on hypergraphs. Electronic Journal of Probability 24, pp. 73. ISSN 1083-6489.
- Muirhead, S. and Pymar, Richard and dos Santos, R.S. (2019) The Bouchaud-Anderson model with double-exponential potential. The Annals of Applied Probability 29 (1), pp. 264-325. ISSN 1050-5164.
- Muirhead, S. and Pymar, Richard and Sidorova, N. (2017) Delocalising the Parabolic Anderson Model through partial duplication of the potential. Probability Theory and Related Fields 171 (3-4), pp. 917-979. ISSN 0178-8051.
- Chaumont, L. and Malécot, V. and Pymar, Richard and Sbai, C. (2016) Reconstructing pedigrees using probabilistic analysis of ISSR amplification. Journal of Theoretical Biology 412, pp. 8-16. ISSN 0022-5193.
- Muirhead, S. and Pymar, Richard (2016) Localisation in the Bouchaud-Anderson model. Stochastic Processes and their Applications 126 (11), pp. 3402-3462. ISSN 0304-4149.
- Pymar, Richard and Sousi, P. (2014) A permuted random walk exits faster. Latin American Journal of Probability and Mathematical Statistics 11 (1), pp. 185-195. ISSN 1980-0436.
- Berestycki, N. and Pymar, Richard (2012) Effect of scale on long-range random graphs and chromosomal inversions. The Annals of Applied Probability 22 (4), pp. 1328-1361. ISSN 1050-5164.
External Repositories