Email: sete at math.tu-berlin.de

Research

I'm a postdoctoral researcher in mathematics. My research interests are in numerical mathematics, computational complex analysis, and their applications in mathematics and the sciences. They include:

• approximation theory, in particular rational approximation and polynomial approximation
• numerical methods for the Helmholtz equation
• conformal mapping and potential theory
• harmonic mappings and their application in gravitational lensing in astrophysics

Profiles:

• Google Scholar
• MathSciNet
• ORCID

Prizes

• Frontiers of Science Award together with Yuji Nakatsukasa and Nick Trefethen for “The AAA algorithm for rational approximation”, awarded at the International Congress of Basic Science 2023.

Publications

Recent publications and Preprints

1. Klaus Schiefermayr and Olivier Sète, Walsh's conformal map onto lemniscatic domains for several intervals, 2024, submitted. arXiv
2. Yuji Nakatsukasa, Olivier Sète, and Lloyd N. Trefethen, The first five years of the AAA algorithm, 2023, submitted. arXiv

Refereed Journal Publications

1. Olivier Sète and Jan Zur, On the zeros of polyanalytic polynomials, Journal of Mathematical Analysis and Applications, 540(1) (2024), 128595. arXiv
2. Klaus Schiefermayr and Olivier Sète, Walsh's conformal map onto lemniscatic domains for polynomial pre-images II, Computational Methods and Function Theory, 24 (2024), pp. 257-281. arXiv
3. Roland Pulch and Olivier Sète, Stochastic Galerkin method and port-Hamiltonian form for linear first-order ordinary differential equations, International Journal for Uncertainty Quantification, 14(4) (2024), pp. 65-82. arXiv
4. Roland Pulch and Olivier Sète, The Helmholtz equation with uncertainties in the wavenumber, Journal of Scientific Computing, 98(3) (2024), article number 60. arXiv
5. Klaus Schiefermayr and Olivier Sète, Walsh's conformal map onto lemniscatic domains for polynomial pre-images I, Computational Methods and Function Theory, 23 (2023), pp. 489-511. arXiv
6. Sergei Kalmykov, Béla Nagy, and Olivier Sète, Minimal degree rational open up mappings and related questions, Annales Fennici Mathematici, 48(2) (2023), pp. 429-451. arXiv
7. Jörg Liesen, Mohamed M.S. Nasser, and Olivier Sète, Computing the logarithmic capacity of compact sets having (infinitely) many components with the Charge Simulation Method, Numerical Algorithms, 93 (2023), pp. 581-614. arXiv
8. Olivier Sète and Jan Zur, The transport of images method: computing all zeros of harmonic mappings by continuation, IMA Journal of Numerical Analysis, 42(3) (2022), pp. 2403-2428. Free access article link. arXiv
9. Luis García Ramos, Olivier Sète, and Reinhard Nabben, Preconditioning the Helmholtz equation with the shifted Laplacian and Faber polynomials, Electronic Transactions on Numerical Analysis, vol. 54, 2021, pp. 534-557.
10. Olivier Sète and Jan Zur, Number and location of pre-images under harmonic mappings in the plane, Annales Fennici Mathematici, 46(1) (2021), 225–247. arXiv
11. Robert Luce and Olivier Sète, The index of singular zeros of harmonic mappings of anti-analytic degree one, Complex Variables and Elliptic Equations, 66:1 (2021), 1-21. Available as Oberwolfach Preprint OWP 2017-03. arXiv
12. Olivier Sète and Jan Zur, A Newton method for harmonic mappings in the plane, IMA Journal of Numerical Analysis, 40(4) (2020), pp. 2777-2801. Free access article link. arXiv
13. Yuji Nakatsukasa, Olivier Sète, and Lloyd N. Trefethen, The AAA algorithm for rational approximation, SIAM Journal on Scientific Computing, 40-3 (2018), pp. A1494-A1522. arXiv
14. Jörg Liesen, Olivier Sète, and Mohamed M.S. Nasser, Fast and Accurate Computation of the Logarithmic Capacity of Compact Sets, Computational Methods and Function Theory, 17(4) (2017), 689-713. arXiv
15. Olivier Sète and Jörg Liesen, Properties and examples of Faber--Walsh polynomials, Computational Methods and Function Theory, 17(1) (2017), 151-177. arXiv
16. Mohamed M.S. Nasser, Jörg Liesen, and Olivier Sète, Numerical computation of the conformal map onto lemniscatic domains, Computational Methods and Function Theory, 16(4) (2016), 609-635. arXiv
17. Olivier Sète and Jörg Liesen, On conformal maps from multiply connected domains onto lemniscatic domains, Electronic Transactions on Numerical Analysis, vol. 45, pp. 1-15, 2016. arXiv
18. Robert Luce, Olivier Sète, and Jörg Liesen, A Note on the Maximum Number of Zeros of r(z)−z̅, Computational Methods and Function Theory, 15(3) (2015), 439-448. arXiv
19. Olivier Sète, Robert Luce, and Jörg Liesen, Creating images by adding masses to gravitational point lenses (Editor's Choice), General Relativity and Gravitation, 47, Article number: 42, 2015. arXiv
20. Olivier Sète, Robert Luce, and Jörg Liesen, Perturbing rational harmonic functions by poles, Computational Methods and Function Theory, 15(1) (2015), 9-35. arXiv
21. Robert Luce, Olivier Sète, and Jörg Liesen, Sharp parameter bounds for certain maximal point lenses (Editor's Choice), General Relativity and Gravitation, 46, Article number: 1736, 2014. arXiv

Further Publications

1. Sergei Kalmykov, Béla Nagy, and Olivier Sète, Rational Interpolation and Open-Up Mappings, Mathematical Notes, 112, 483-487 (2022).
2. Jussi Behrndt and Olivier Sète, On the nonreal eigenvalues of elliptic differential operators with indefinite weights on Lipschitz domains, Proceedings in Applied Mathematics and Mechanics, 9 (2009), 667-668; pdf.

Theses

1. Olivier Sète, On Interpolation and Approximation Problems in Numerical Linear Algebra, Doktorarbeit (PhD Thesis), Technische Universität Berlin, 2016.
2. Olivier Sète, Ein Modell für unendlichdimensionale singuläre Störungen von elliptischen Differentialoperatoren, Diplomarbeit (Diploma Thesis), Technische Universität Berlin, 2009.

Software

• Transport of images Toolbox
  with Jan Zur, A Matlab Toolbox to compute zeros of harmonic mappings, 2020.
• Polynomial preconditioners for the Helmholtz equation based on Faber polynomials
  with Luis García Ramos. Matlab-Code with discretization of the Helmholtz equation and implementation of the Faber preconditioner from the article [L. García Ramos, O. Sète, R. Nabben, Preconditioning the Helmholtz equation with the shifted Laplacian and Faber polynomials, ETNA, 2021].

Selected talks

• Polynomial preconditioning with Faber polynomials for the Helmhotz equation
  25th conference of the Inernational Linear Algebra Society (Madrid, Spain), 16 June 2023.
• Solving the Helmholtz equation with uncertainties in the wavenumber
  GAMM Workshop on Applied and Numerical Linear Algebra 2022 (Prag, Czech Republic), 23 September 2022.
• A continuation method to find all zeros of planar harmonic mappings
  41st Northern German Colloquium on applied analysis and numerical mathematics (Hannover, Germany), 17th June 2022.
• Computation of the logarithmic capacity
  Complex Approximations, Orthogonal Polynomials and Applications (CAOPA) Seminar Series (Moscow, Russia, Online), 21th February 2022.
• Number and location of pre-images under planar harmonic mappings
  Computational Methods and Function Theory 2021 (Valparaíso, Chile, held online), 12th January 2022.
• Polynomial preconditioning with truncated Faber series and an application to the Helmholtz equation
  GAMM Workshop Applied and Numerical Linear Algebra 2021 (Potsdam, Germany), 17th September 2021.
• Conformal mapping of multiply connected domains onto lemniscatic domains and the computation of the logarithmic capacity
  13th ISAAC Congress (Ghent, Belgium, held online), 3rd August 2021.
• Caustics of harmonic mappings and their effect on the number of pre-images
  Institut für Angewandte Analysis, TU Bergakademie Freiberg (Freiberg, Germany), 18th February 2020.
• Computing Walsh's conformal map onto lemniscatic domains,
  invited speaker at CATW03, Computational complex analysis, Isaac Newton Institute (Cambridge, UK), 13th December 2019.
• On the Valence of Harmonic Mappings in the Plane
  First Analysis Mathematica International Conference (Budapest, Hungary), 16th August 2019.

Teaching

Teaching as lecturer

I was a lecturer of the following courses.

Teaching as teaching assistant at Universität Greifswald

Teaching as teaching assistant at TU Berlin

Teaching as student teaching assistant at TU Berlin

I was a student teaching assistant (Tutor) of the following courses at TU Berlin.