Sören Sprehe 

My name is Sören Sprehe and I am a postdoctoral  fellow in the arithmetic geometry group at the University Bielefeld. You can find my CV  here. 

I obtained my Dr. math. (i.e. my Ph.D.) in 2025 under the supervision of Dr. Lennart Gehrmann. 

I am particulary interested in explicit class field theory and the p-adic Kudla program. More precisely, I am working on questions related to rigid meromorphic cocycles, which were defined by Henri Darmon and Jan Vonk  here. In my thesis, I used the work of  Darmon, Gehrmann and Lipnowski to relate rigid meromorphic cocycles for O(2,2) to rigid meromorphic cocycles for O(2,1) (i.e. to Darmon-Vonk cocycles). This approach gives a two-variable description of a function introduced by Darmon-Vonk which is expected to behave like the difference of two singular moduli. Using this reinterpretation I established the (anti)symmetry of this function. A crucial ingredient for this result is a statement about invertible analytic functions on the product of two copies of the p-adic upper half planes, which is proved in the Appendix of my thesis. 

Beside of mathematics, I am a (subprofessional) runner, aiming to run a marathon at some point in my life. If you are interested, find here my profil on Strava.