ALGAR 2020: Lecture series

In 2020, I was one of the main speakers at the yearly summer school Algebra and Arithmetic (ALGAR), which in that year had as its topic Valuations, quadratic forms, and definability.
The summer school took place online this year, and the talks have been recorded and are made available. Below you may find the slides and recordings of my talks.

1. A universal definition of $\mathbb{Z}$ in $\mathbb{Q}$: slides, recording
2. Existential definitions: from local to global fields slides, recording
3. Valuations on function fields slides, recording
4. Defining subrings in p-adic function fields slides, recording