M.Sc. P. Tobias WernerBild: Sonja Rode

Tobias Werner

Fachgebiet Stochastik
Institut für Mathematik | Uni Kassel

Adresse
Universität Kassel
Institut für Mathematik
Heinrich-Plett-Straße 40
34132 Kassel
Raum 1416

Telefon
+49 561 804-4477

E-Mail:
twerner@mathematik.uni-kassel.de

Research

Research Interests

  • Stochastich (partial) differential equations
  • Regularity theory
  • Weighted function spaces
  • Functional analysis
  • Numerics for stochastic differential equations
  • Neural networks

My research lies in the analysis of partial and stochastic partial differential equations (PDEs and SPDEs), with a particular focus on questions of well-posedness and regularity. Broadly speaking, I study when such equations admit unique solutions, how the different terms in the equation influence the behaviour of those solutions, and how much irregularity in the data, coefficients, and nonlinearities can still be allowed.

SPDEs arise naturally in many areas of science and engineering, including fluid dynamics, diffusion processes, filtering theory, and mathematical finance. A central challenge in their analysis is the development of robust linear theories that can later be used to treat nonlinear problems. One key concept in this context is stochastic maximal regularity, which provides a powerful framework for obtaining sharp existence, uniqueness, and regularity results.

A particular emphasis of my work is on SPDEs posed on domains with singular boundaries, such as corners, edges, and conic points. While such geometries occur naturally in applications, they create substantial mathematical difficulties: standard Sobolev regularity fails, as solutions typically develop singular behaviour near the boundary or at geometric singularities. To address this, I work with weighted function spaces that capture these local effects in a precise way.

In recent work, I developed a regularity theory for the Dirichlet Laplacian on conic domains by proving bounded holomorphic functional calculus results in weighted Lp-spaces. These results substantially strengthen the deterministic theory and provide a foundation for maximal regularity methods for nonlinear SPDEs on non-smooth domains.

Publications / Preprints

2. The H-calculus for the Dirichlet-Laplacian on conical domains. 
(with P. A. Cioica-Licht, E. Lorist)
Submitted.
[arXiv:2509.09519]
1. Deep neural networks overcome the curse of dimensionality in the numerical approximation of semilinear partial differential equations.
(with P. A. Cioica-Licht, M. Hutzenthaler)
To appear in Communications in Mathematical Sciences.
[arXiv:2205.14398]

Curriculum Vitae

Professional experience

Since 11/2021Research Assistant (PhD Candidate), Stochastics Group, Institute of Mathematics, University of Kassel, Germany
10/2020 – 10/2021Teaching Assistant, Stochastic Analysis Group, Faculty of Mathematics, University of Duisburg-Essen, Germany

Education

Since 11/2021PhD student at University of Kassel
Dissertation (working title): Differential operators on domains with corners and edges and applications to SPDE
Advisor: Dr. Petru A. Cioica-Licht
2019 – 2021Master’s Program in Mathematics (Major) and Business Administration (Minor), University of Duisburg-Essen
Thesis: Deep neural networks overcome the curse of dimensionality in the numerical approximation of semilinear partial differential equations
Advisor: Prof. Dr. Martin Hutzenthaler
2015 – 2018Bachelor’s Program in Mathematics (Major) and Business Administration (Minor), Ulm University
Thesis: Advanced container stacking strategies
Advisor: Prof. Dr. Henning Bruhn-Fujimoto
2024DAAD-Scholarship for a 2 months research stay at Delft University of Technology, the Netherlands
2022 Best thesis award 2021 of the University of Duisburg-Essen, Mathematics Section

 

01/2025PDE Seminar, Delft University of TechnologyThe H-calculus of the Dirichlet-Laplacian on a wedge
12/2024Analysis Seminar, University of KasselThe stochastic heat equation and the Dirichlet-Laplacian on a wedge
05/2022Stochastic Analysis Seminar, University of Duisburg-EssenNeural networks overcome the curse of dimensionality in the numerical approximation for semilinear PDE
04/2025Analysis and Probability in Infinite Dimensions, Bad HerrenalbPoster: H-Calculus for differential operators in domains with corners and edges
03/2025Maximal Regularity Methods in Mathematical Fluid Mechanics, FrankensteinTalk: SPDEs on non-smooth domains: An operator theoretic perspective
11/2025Recent Developments in SPDEs and BSDEs meet Harmonic and Functional Analysis, Oberwolfach
06/2025Stochastic Partial Differential Equations in Critical Spaces, Oberwolfach
07/2024SPDEs below sealevel, Delft
05/2024SPDEvent III, Bielefeld
08/202318th PhD Student Convent of Stochastics, Heidelberg
07/2023SPDEvent II, Bielefeld
04/202316th German Probability and Statistics Days, Essen
09/2022Westphalian Stochastics Days, Paderborn
09/2024 - 10/2024Delft University of Technology, the Netherlands
Host: Prof. Dr. Mark C. Veraar
Summer 2025Teaching Assistant for the course Biometrics: Statistics for Biologists (Dr. Petru A. Cioica-Licht), University of Kassel
Winter 2024Teaching Assistant for the course Stochastic Differential Equations (Dr. Markus Antoni), University of Kassel
Winter 2025, 2024, 2023, 2022Teaching Assistant for the course Measure and Probability Theory (Dr. Petru A. Cioica-Licht), University of Kassel
Summer 2023, 2022Teaching Assistant for the course Stochastic Processes (Dr. Petru A. Cioica-Licht), University of Kassel
Summer 2021Tutor for the course Probability Theory 1 (Prof. Dr. Martin Hutzenthaler), University of Duisburg-Essen
Winter 2020Tutor for the course Stochastik (Prof. Dr. Martin Hutzenthaler), University of Duisburg-Essen