# Staff Profile

## Dr David Seifert

### Reader in Pure Mathematics

- Email: david.seifert@ncl.ac.uk
- Telephone: +44 (0)191 208 5882
- Address:

School of Mathematics, Statistics & Physics

Herschel Building

Newcastle University

Newcastle upon Tyne

NE1 7RU, United Kingdom

I am a member of the Pure Mathematics group in the School of Mathematics, Statistics and Physics. I chair the School's EDI Committee, and I oversee the School's mentoring scheme for postgraduate research students. I represent the UK on the managing committee of an EU-funded project on *Mathematical Models for Interacting Dynamics on Networks* (COST Action 18232), and I am a member of the London Mathematical Society and the European Mathematical Society. I have been a Fellow of the UK Higher Education Academy (Advance HE) since 2017.

Before arriving in Newcastle I was at the University of Oxford, most recently as a fellow of St John's College, and before that as an undergraduate and later graduate student at Hertford College and Balliol College, respectively. I completed my Habilitation at TU Dresden, Germany.

My area of research is operator theory, and I am particularly interested in the quantitative asymptotic behaviour of operator semigroups. My work combines elements of functional analysis, harmonic analysis and complex analysis, and it has applications in the study of energy decay of damped waves, in some areas of mathematical control theory and in the theory of iterative methods.

I recently co-organised the conference New Challenges in Operator Semigroups, which was held in St John's College, Oxford.

My work has received generous financial support from various sources, including the London Mathematical Society, the Heilbronn Institute for Mathematical Research, the Engineering and Physical Sciences Research Council and the European Cooperation in Science and Technology (COST).

I welcome enquiries from prospective Master's students, PhD students and postdocs in my area of expertise.

In the academic year 2022/23 I am teaching the following courses:

- Group Project - MAS3091
- Linear Analysis - MAS3702

- Dell'Oro F, Seifert D. A short elementary proof of the Gearhart-Prüss theorem for bounded semigroups.
*In: Control & Inverse Problems*. 2022, Springer Nature. In Press. - Batty CJK, Seifert D. A Katznelson-Tzafriri theorem for analytic Besov functions of operators.
*Journal of Operator Theory*2022. In Press. - Dell'Oro F, Paunonen L, Seifert D. Optimal decay for a wave-heat system with Coleman-Gurtin thermal law.
*Journal of Mathematical Analysis and Applications*2023,**518**(2), 126706. - Batty CJK, Seifert D. A continuous-parameter Katznelson-Tzafriri theorem for algebras of analytic functions.
*Studia Mathematica*2022, Epub ahead of print. - Batty CJK, Seifert D. Some developments around the Katznelson-Tzafriri theorem.
*Acta Scientiarum Mathematicarum*2022. In Press. - Chill R, Paunonen L, Seifert D, Stahn R, Tomilov Y. Non-uniform stability of damped contraction semigroups.
*Analysis & PDE*2021. In Press. - Ng ACS, Seifert D. Optimal rates of decay in the Katznelson-Tzafriri theorem for operators on Hilbert spaces.
*Journal of Functional Analysis*2020,**279**(12), 108799. - Chill R, Seifert D, Tomilov Y. Semi-uniform stability of operator semigroups and energy decay of damped waves.
*Philosophical Transactions A*2020,**378**(2185), 20190614. - Hibble SJ, Chippindale AM, Zbiri M, Rees NH, Keeble DS, Wilhelm H, d'Abrumenil S, Seifert D. Intra- and Interchain Interactions in (Cu
_{1/2}Au_{1/2})CN, (Ag_{1/2}Au_{1/2})CN, and (Cu_{1/3}Ag_{1/3}Au_{1/3})CN and Their Effect on One-, Two-, and Three-Dimensional Order.*Inorganic Chemistry*2020,**59**(16), 11704–11714. - Paunonen L, Seifert D. Asymptotics and approximation of large systems of ordinary differential equations.
*Systems & Control Letters*2020,**140**, 104703. - Ng ACS, Seifert D. Optimal energy decay in a one-dimensional wave-heat system with infinite heat part.
*Journal of Mathematical Analysis and Applications*2020,**482**(2), 123563. - Debruyne G, Seifert D. Optimality of the quantified Ingham-Karamata theorem for operator semigroups with general resolvent growth.
*Archiv der Mathematik*2019,**113**(6), 617–627. - Debruyne G, Seifert D. An abstract approach to optimal decay of functions and operator semigroups.
*Israel Journal of Mathematics*2019,**233**(1), 439-451. - Paunonen L, Seifert D. Asymptotics for periodic systems.
*Journal of Differential Equations*2019,**266**(11), 7152-7172. - Rozendaal J, Seifert D, Stahn R. Optimal rates of decay for operator semigroups on Hilbert spaces.
*Advances in Mathematics*2019,**346**, 359-388. - Batty CJK, Paunonen L, Seifert D. Optimal energy decay for the wave-heat system on a rectangular domain.
*SIAM Journal on Mathematical Analysis*2019,**51**(2), 808-819. - Mokhtar-Kharroubi M, Seifert D. Rates of convergence to equilibrium for collisionless kinetic equations in slab geometry.
*Journal of Functional Analysis*2018,**275**(9), 2404-2452. - Paunonen L, Seifert D. Asymptotic behaviour of coupled systems in discrete and continuous time.
*Journal of Dynamics and Differential Equations*2018,**30**(2), 433-444. - Darwin O, Jha A, Roy S, Seifert D, Steele R, Stigant L. Non-optimality of the Greedy Algorithm for subspace orderings in the method of alternating projections.
*Results in Mathematics*2017,**72**(1), 979-990. - Badea C, Seifert D. Quantified asymptotic behaviour of Banach space operators and applications to iterative projection methods.
*Pure and Applied Functional Analysis*2017,**2**(4), 585-598. - Paunonen L, Seifert D. Asymptotic behaviour in the robot rendezvous problem.
*Automatica*2017,**79**, 127-130. - Paunonen L, Seifert D. Asymptotics for infinite systems of differential equations.
*SIAM Journal on Control and Optimization*2017,**55**(2), 1153-1178. - Paunonen L, Seifert D. Asymptotic behaviour of platoon systems.
*In: 22nd International Symposium on Mathematical Theory of Networks and Systems*. 2016, Minnesota, MN, USA. - Badea C, Seifert D. Ritt operators and convergence in the method of alternating projections.
*Journal of Approximation Theory*2016,**205**, 133-148. - Chill R, Seifert D. Quantified versions of Ingham’s theorem.
*Bulletin of the London Mathematical Society*2016,**48**(3), 519-532. - Batty CJK, Paunonen L, Seifert D. Optimal energy decay in a one-dimensional coupled wave-heat system.
*Journal of Evolution Equations*2016,**16**(3), 649–664. - Seifert D. Rates of decay in the classical Katznelson-Tzafriri theorem.
*Journal d'Analyse Mathématique*2016,**130**(1), 329-354. - Seifert D. A quantified Tauberian theorem for sequences.
*Studia Mathematica*2015,**227**, 183-192. - Seifert D. A Katznelson–Tzafriri Theorem for Measures.
*Integral Equations and Operator Theory*2015,**81**(2), 255–270. - Seifert D. Some improvements of the Katznelson-Tzafriri theorem on Hilbert space.
*Proceedings of the American Mathematical Society*2015,**143**, 3827-3838.