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Meeting on Tuesdays at 5:30-6:45 Room 622

Seminar on Abelian Varieties

Week 1: Basic Properties of Abelian Varieties
01.28.25 Sofia Wood

We define an abelian varieties. We define isogenies of abelian varieties and give some properties of isogenies. We prove some basic properties including the following: abelian varieties are commutative, the relative dualizing sheaf is trivial and we prove that all rational maps from a nonsingular variety to an abelian variety extend to a morphism.​

Week 2: Projectivity of Abelian Varieties
02.04.25 Anna Abasheva

We show that all abelian varieties are projective, not just proper. The proof can be thought of as a generalization of the fact that every elliptic curve embeds into a 2-dimensional projective space via a Weierstrass equation.

 

In the notes and time permitting, we discuss which n it is possible to embed an abelian variety of dimension g into projective space of dimension n. It turns out that in general, for an abelian variety of dimension g, the smallest such value of n is 2g+1. Note that the case of elliptic curves, all of which can be embedded in 2-dimensional projective space via a Weierstrass equation are an exception.

Week 3: Dual Abelian Varieties
02.11.25 Nicolás Vilches Reyes

We define the dual abelian variety of a given abelian variety, explain its universal property and sketch the proof of existence. 

Week 4: The Tate Module of an Abelian Variety and Etale cohomology of abelian varieties
02.18.25 Carlos Alvarado

We give an overview of some basic theorems in étale cohomology and explain why the Zariski site sails. We then compute the étale cohomology of abelian varieties and relate it to their Tate module.

Week 5: Endomorphisms of Elliptic curves
02.25.25 Sofia Wood

We study endomorphism rings in the case of elliptic curves. We show that there are only 3 possible types of endomorphism ring. We will be particulatly inteserted in elliptic curves with complex multiplication. We show by considering class groups of orders of imaginary quadratic number fields that there are precisely 13 elliptic curves defined over Q (up to isomorphism). We also discuss how CM elliptic curves are related to class field theory.

Week 6: Zeta Functions of Abelian Varieties
03.04.25 Lisa Faulkner Valiente

We give a result allowing us to count the number of F_q^m points on an abelian variety over a closure of F_q using the Frobenius endomorphism. We then define the zeta function of an abelian variety and discuss how this gives a Riemann Zeta function.

Week 7: Computational Aspects of Elliptic Curves
03.25.25 Hechen Hu

We will concentrate on elliptic curves over number fields and discuss how one might actually carry out computations. More specifically, I'll discuss how to determine the places of good reduction, the torsion group, and coefficients of the L-series.

Week 8: Heights on Abelian Varieties and the Mordell-Weil Theorem
04.01.25 Sofia Wood

We discuss heights on abelian varieties, prove a finiteness result and sketch the proof of the Mordell-Weil theorem.

Week 9: Jacobian Varieties
04.08.25 Amal Mattoo

We introduce Jacobian varieties of curves, first abstractly as representable functors and then constructing them as abelian varieties. We prove some basic properties of the Jacobian variety, such as its dimension, and briefly show some applications such as to the Weil Conjectures. 

Week 10: Neron Models
04.15.25 Matthew Hase-Liu

Precise topics to be determined.

Week 11: Moduli Space of Abelian Varieties Part 1
04.22.25 Rafah Hajjar Muñoz

Precise topics to be determined.

Week 12: Moduli Space of Abelian Varieties Part 2
04.29.25 Sofia Wood

Precise topics to be determined

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