##### Department of Mathematics,

University of California San Diego

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### Math 209 - Number Theory Seminar

## Kiran Kedlaya

#### UCSD

## Orders of abelian varieties over $\mathbb{F}_2$

##### Abstract:

We describe several recent results on orders of abelian varieties over $\mathbb{F}_2$: every positive integer occurs as the order of an ordinary abelian variety over $\mathbb{F}_2$ (joint with E. Howe); every positive integer occurs infinitely often as the order of a simple abelian variety over $\mathbb{F}_2$; the geometric decomposition of the simple abelian varieties over $\mathbb{F}_2$ can be described explicitly (joint with T. D'Nelly-Warady); and the relative class number one problem for function fields is reduced to a finite computation (work in progress). All of these results rely on the relationship between isogeny classes of abelian varieties over finite fields and Weil polynomials given by the work of Weil and Honda-Tate. With these results in hand, most of the work is to construct algebraic integers satisfying suitable archimedean constraints.

### October 7, 2021

### 2:00 PM

In person: AP&M 7321 ; Zoom: https://kskedlaya.org/nts.cgi

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