Lethbridge Number Theory and Combinatorics Seminar: Soroosh Yazdani

In 1979 G. Belyi proved that given any smooth curve $C$ over any number field, there is map $\beta:C \rightarrow \mathbb{P}^1$ such that $\beta$ is unramified outside of three points. This is particularly striking since Belyi's theorem is not true over complex numbers, and hence it is an arithmetic result as much as it is a geometric result. In this talk I will give a brief explanation for the proof of this theorem and explain how this theorem can be used to relate arithmetic geometry problems to the ABC conjecture.