FernUni/UniDistance

Faculty of Mathematics and Computer Science

Schinerstrasse 18

3900 Brig

rosa.winter (at) unidistance.ch

I am a postdoc in number theory at the FernUni Schweiz/UniDistance Suisse.

From 2021 until 2024 I was a research associate in the Number Theory Group of King's College London, working with Rachel Newton. Before that I was a postdoctoral researcher in the Nonlinear Algebra group of Bernd Sturmfels at MPI-MiS in Leipzig. I was a PhD student under the supervision of Martin Bright and Ronald van Luijk at Universiteit Leiden between 2016 and 2020.

My research interests are mainly in arithmetic geometry, more specifically, in the arithmetic of surfaces. I mostly focus on low-degree del Pezzo surfaces, and study their arithmetic, geometric, and combinatorial aspects. More broadly, I like to explore applications of algebraic geometry and number theory to other areas of mathematics.

From 2021 until 2024 I was a research associate in the Number Theory Group of King's College London, working with Rachel Newton. Before that I was a postdoctoral researcher in the Nonlinear Algebra group of Bernd Sturmfels at MPI-MiS in Leipzig. I was a PhD student under the supervision of Martin Bright and Ronald van Luijk at Universiteit Leiden between 2016 and 2020.

My research interests are mainly in arithmetic geometry, more specifically, in the arithmetic of surfaces. I mostly focus on low-degree del Pezzo surfaces, and study their arithmetic, geometric, and combinatorial aspects. More broadly, I like to explore applications of algebraic geometry and number theory to other areas of mathematics.

- [10]
**Generalized Eckardt points on del Pezzo surfaces of degree 1**(with J. Desjardins, Y. Fu and K. Isham).*Submitted*.

Link to arXiv (2024). - [9]
**Weak weak approximation and the Hilbert property for degree-two del Pezzo surfaces**(with J. Demeio and S. Streeter).*Submitted*.

Link to arXiv (2023). - [8]
**Campana points on diagonal hypersurfaces**(with F. Balestrieri, J. Brandes, M. Kaesberg, M. Pieropan, and J. Ortmann).*Accepted for publication in Women in Numbers Europe 4 - Research Directions in Number Theory.*.

Link to arXiv (2023). - [7]
**Torsion points and concurrent exceptional curves on del Pezzo surfaces of degree one**(with J. Desjardins).*Submitted*.

Link to arXiv (2022), and magma code. - [6]
**Recovery from Power Sums**(with B. Sturmfels and H. Melánová). Experimental Mathematics (2022).

Link to the journal (open access). - [5]
**Density of rational points on a family of del Pezzo surfaces of degree one**(with J. Desjardins). Advances in Mathematics, Vol 405 (2022).

Link to the journal (open access), and magma code. - [4]
**Linear Spaces of Symmetric Matrices with Non-Maximal Maximum Likelihood Degree**(with Y. Jiang and K. Kohn). Le Matematiche, Vol 76 No 2 (2021), pp. 461-481.

Link to the journal (open access). - [3]
**Fields of definition of elliptic fibrations on covers of certain extremal rational ellipic surfaces**(with V. Cantoral-Farfán, A. Garbagnati, C. Salgado, and A. Trbović). Women in Numbers Europe III: Research Directions in Number Theory. Springer, Association for Women in Mathematics Series, Vol 24 (2021), pp. 171-205.

Link to the book, and to the accepted version on arXiv. - [2]
**Concurrent exceptional curves on del Pezzo surfaces of degree one**(with R. van Luijk). Mathematics of Computation, Vol 92 (2023), pp. 451-481.

Link to the journal, and to the accepted version on arXiv, with magma code 1 and magma code 2. - [1]
**The action of the Weyl group on the**(with R. van Luijk). Graphs and Combinatorics, Vol 37 No 6 (2021), pp. 1965-2064.*E*root system_{8}

Link to the journal (open access), and to the accepted version on arXiv, with magma code. - PhD thesis: Geometry and arithmetic of del Pezzo surfaces of degree 1 (2021).
- Master thesis: Concurrent exceptional curves on del Pezzo surfaces of degree one (2014).
- Bachelor thesis: Elliptic curves over
**Q**_{p}(2011).

- OSCAR code with with some basic commands for number theory in OSCAR.
- Magma code used in Chapter 2 of my PhD thesis.
- Magma code used in Chapter 5 of my PhD thesis.

- 21/09/2023 An Afternoon of Diophantine Geometry, University of Manchester.
- 23/07/2023 Rational Points 2023, Franken-Akademie Schloss, Schney.
- 19/06/2023 Number Theory Seminar, Georg-August-Universität Göttingen.
- 12/06/2023 Foundations of Computational Mathematics 2023, Computational Number Theory workshop, Paris.
- 12/05/2023 Seminar Variétés Rationnelles, Sorbonne Université, Paris.
- 15/02/2023 Heilbronn Seminar, University of Bristol.
- 09/01/2023 Great Western Number Theory seminar, University of Oxford.
- 12/12/2022 The Advent of Rational Points, King's College London.
- 22/11/2022 Cambridge Number Theory Seminar, University of Cambridge.
- 14/11/2022 Number Theory Seminar, University of Warwick.
- 7/10/2022 Workshop on Solving Polynomial Equations and Applications, CWI, Amsterdam.
- 21/09/2022 Seminar in coding theory and cryptography, Université de Neuchâtel.
- 27/05/2022 Symbolic Computation Istanbul Meetings, Istanbul.
- 26/04/2022 Rational Points on Higher-Dimensional Varieties, ICMS, Edinburgh.
- 16/03/2022 Number/Representation Theory seminar (online), University of Toronto.
- 03/03/2022 Number Theory Seminar, University of Oxford.
- 02/03/2022 AGNT Seminar (online), Rice University, Houston.
- 04/02/2022 Algebra & Number Theory Seminar, Queen Mary University of London.
- 17/11/2021 London Number Theory Seminar, Imperial College London.
- 11/11/2021 Zoom Algebraic Geometry Seminar (ZAG).
- 07/07/2021 Browning group working seminar (online), IST Austria, Vienna.
- 22/06/2021 Nonlinear Algebra Seminar, MPI-MiS, Leipzig.
- 25/02/2021 Number Theory Seminar (online), University of California Irvine.
- 19/02/2021 Zoom On Rational Points (ZORP).
- 02/02/2021 Nonlinear Algebra Seminar Online, MPI-MiS Leipzig.
- 17/12/2020 Séminaire Arithmétique et Théorie de l’Information (online), Aix-Maseille Université.
- 11/11/2020 Algebra Seminar (online), Rijksuniversiteit Groningen.
- 29/10/2020 Quarantined Number Theory and Algebraic Geometry Seminar (online), Simon Fraser University.
- 22/09/2020 Arithmetic Geometry Seminar (online), Ohio State University.
- 03/06/2020 PhD colloquium (online), Universiteit Leiden.
- 14/04/2020 Nonlinear Algebra Seminar Online, MPI-MiS Leipzig.
- 26/02/2020 Heilbronn Number Theory Seminar, University of Bristol.
- 07/02/2020 Intercity Number Theory Seminar, Universiteit Leiden.
- 18/12/2019 Seminario di Natale, Università degli Studi di Milano.
- 11/12/2019 Number Theory Seminar, Københavns Universitet.
- 06/03/2019 Number/Representation Theory seminar, University of Toronto.
- 26/06/2018 Konstanz Women in Mathematics lecture series, Universität Konstanz.
- 31/05/2018 Bernoullis Tafelrunde Graduate Student Seminar, Universität Basel.
- 18/06/2018 Poster at GAeL XXVI, Université de Strasbourg.
- 21/03/2018
*Counting Curves*, Tropical Geometry Seminar, Universiteit Leiden. - 11/09/2017 Poster at Diophantine problems (DIOP), University of Manchester.
- 07/07/2017 Research talk at XXX-èmes Journées Arithmétiques, Université de Caen Normandie.
- 15/02/2017
*Introduction to local-global principles: the Hasse principle and weak approximation*, Seminar 'Obstructions to local-global principles', Universiteit Leiden. - 02/11/2016
*Isogenies*, Seminar 'Good reduction of Abelian Varieties', University of Amsterdam.

- London Number Theory Study Group on Manin's Conjecture and Szemerédi Regularity (spring 2023), co-organized with Ming Ng.
- Algebraic Statistics Seminar (fall 2018), co-organized with Rianne de Heide and Garnet Akeyr.
- Tropical Geometry Seminar (spring 2018), co-organized with Garnet Akeyr.
- Obstructions to local-global principles (spring 2017), co-organized with Julian Lyczak and Erik Visse.

- Spring 2024: M04: Linear Algebra 1, FernUni Schweiz
- Summer 2022: Supervision of two master's students, King's College London
- Fall 2016 - Fall 2019: Calculus (Teacher), Leiden University College, The Hague
- Spring 2018: Elliptic curves (Teaching assistant), Dutch Mastermath course
- Fall 2013: Rational Points on Varieties (Teaching assistant), Dutch Mastermath course
- From 2014 until 2016 I was a mathematics teacher at Calandlyceum Amsterdam, as part of the traineeship Eerstde Klas.