Nikolas Kirschstein

Hi, I hope you’re having a wonderful day! I’m a research-focused mathematician and informatician enthusiastic about reinforcement learning, causal inference, and randomised algorithms. And I make a point of pointing out that calling informatics “computer science” would be like calling astrophysics “telescope science”… 😉

One of my favourite formulae is the bias-variance decomposition in least-squares regression with risk \(r(a) = \mathbb{E}[(a(X) - Y)^2]\), computed (randomised) algorithm \(A\), and optimal algorithm \(a^*\):

\[\underbrace{\mathbb{E}[r(A)] - r(a^*)}_{\text{expected excess risk}} = \underbrace{\mathbb{E}\left[(\mathbb{E}[A(X) \mid X] - a^*(X))^2\right]}_{\text{expected square bias}} + \underbrace{\mathbb{E}[\mathrm{Var}[A(X) \mid X]]}_{\text{expected variance}}\]

Education

MSc Informatics, TUM, 2025 (expected)
- exchange stay at UNSW Sydney, 2024
MSc Mathematical Sciences, Oxford University, 2023
BSc Computer Science, University of Passau, 2022
BSc Mathematics, University of Passau, 2022

Work Experience

Summer 2023: ML Engineer Intern, Google, California & New York
Summer 2022: Software Engineering Intern, Google, San Francisco
2018-2022: Self-employed Web Developer, Remote, Germany

Publications

The Merit of River Network Topology for Neural Flood Forecasting

Kirschstein, N., Sun, Y. (2024). The Merit of River Network Topology for Neural Flood Forecasting. ICML 2024.

Deep Active Learning for Detection of Mercury’s Bow Shock and Magnetopause Crossings

Julka, S., Kirschstein, N., Granitzer, M., Lavrukhin, A., Amerstorfer, U. (2023). Deep Active Learning for Detection of Mercury’s Bow Shock and Magnetopause Crossings. In: Amini, MR., Canu, S., Fischer, A., Guns, T., Kralj Novak, P., Tsoumakas, G. (eds) Machine Learning and Knowledge Discovery in Databases. ECML PKDD 2022. Lecture Notes in Computer Science(), vol 13716. Springer, Cham.

Deep Active Learning with Artificial Neural Networks for Automatic Detection of Mercury’s Bow Shock and Magnetopause Crossing Signatures in NASA’s MESSENGER Magnetometer Observations

Finding Single-Source Shortest Paths on Planar Graphs with Nonnegative Edge Weights in Linear Time

Scholarships

2020-present: Studienstiftung scholarship of Germany
2018-present: Max Weber Programme of Bavaria
2022-2023: Joan Protheroe Choral Scholarship from Lincoln College, University of Oxford
2022-2023: DAAD fellowship by the German Academic Exchange Service

Service and Leadership

since 2023: Board Member of UniversitätsChor Munich, Germany
2021: Conference Co-organiser, University of Passau, Germany
2020: Student Representative in professorship appointments, University of Passau, Germany
2020: On-call Social Worker, Bavarian Red Cross, Germany