PhD student in number theory · Leiden University
Felix Kalker
I am a PhD student at Leiden University under the supervision of Jan Vonk. I am interested in the interplay between number theory, geometry and analysis. Currently I am trying to find a connection between the evaluations of (rigid) meromorphic cocycles and linking numbers of geodesics in modular curves.
Email: f.s.kalker (at) math.leidenuniv.nl GitHub
Seminars
I have co-organised the following seminars:
- Gross-Zagier formula — Spring 2026, co-organised with Paolo Bordignon and Mateo Crabit Nicolau
- Weil Cohomologies — Fall 2025, co-organised with Paolo Bordignon, Alexander Molyakov and Victor de Vries
Committees
I am or have been a member of the following committees:
- Young KWG — Secretary: 2026–present; Member: 2025
A committee of the Royal Dutch Mathematical Society (KWG) which organises activities for early-career mathematicians in the Netherlands.
- Education Committee — Chair: Fall 2023–Spring 2024; Member: Fall 2022–Spring 2023
This committee helps ensure the quality of education for courses given at the Leiden Mathematical Institute.
Teaching
Ever since the second year of my Bachelor studies, I have been actively involved with teaching. Below is a list of my teaching duties.
As a PhD student
- TA for Algebraic Number Theory — MasterMath, Fall 2026, Amsterdam
- TA for Topics in Algebraic Number Theory — Spring 2026, Leiden
- TA for Algorithms in Algebra — Fall 2025, Leiden
- TA for Algebra 3 (Galois Theory) — Spring 2025, Leiden
- Introductory sessions for new TAs, with Federica Pasquotto - Spring 2025 onwards, Leiden
As a Master’s/Bachelor’s student
- TA for Algebraic Number Theory (MasterMath) — Fall 2024, Utrecht
- TA for Algebra 1 (Group Theory) — Spring 2024, Leiden
- TA for Wiskundige Structuren (Mathematical Structures) — Fall 2023, Leiden
- Weekly one-on-one tutoring sessions for Algebra 2 (Ring Theory) — Fall 2023, Leiden
- Weekly group tutoring sessions for all first-year courses — Academic Year 2023/2024, Leiden
- TA for Algebra 3 (Galois Theory) — Spring 2023, Leiden
- TA for Gewone Differentiaalvergelijkingen (ODEs) — Fall 2022, Leiden
- TA for Moduleren en Simuleren (Modelling) — Spring 2022, Leiden
- TA for Wiskundige Structuren (Mathematical Structures) — Fall 2021, Leiden
- TA for Algebra 1 (Group Theory) — Spring 2021, Leiden
- TA for Wiskundige Structuren (Mathematical Structures) — Fall 2020, Leiden
Writings
- Master’s thesis — The Knopp Cocycle and Cycle Integrals of the j-function
- Bachelor’s thesis — Reduction of Binary Forms over Complex Principal Ideal Domains
Modular knots
Closed geodesics in the complement of the discriminant trefoil. Drag to rotate.