**In Spring 2021, the mode of instruction for this class will be distancelearning.**
Distance learning here means that there will be livestream lectures on Tuesdays and Thursdays 1112:15 (livestream is only available for UConn students), but the lectures and attendance are not mandatory. Lectures will be recorded. Videos of the lectures will be posted to YouTube.
Course Description:
This course will be an introduction to elliptic curves which, roughly speaking, are smooth cubic curves in the projective plane with at least one rational point (turns out they have a simple model of the form y^2=x^3+ax+b). The surprising feature of elliptic curves is that their points can be made into an abelian group, and this group is finitely generated when we focus on points with coordinates in the rational numbers lying on an elliptic curve with rational coefficients. Elliptic curves are central in modern number theory, e.g., they were essential in the proof of Fermat’s Last Theorem. The goal of the course will be to understand and calculate the group of all rational points on an elliptic curve (i.e., calculate its torsion and rank), and a number of more refined invariants (such as the order of the ShafarevichTate group).
The prerequisites for this course are the abstract algebra sequence (Math 5210 and 5211) and a basic understanding of algebraic number theory and algebraic geometry, although I will adjust the material to the audience background as much as I can. Our textbook will be “The Arithmetic of Elliptic Curves,” by J. H. Silverman, which is the standard graduatelevel textbook for the subject.
Prerequisites: MATH 5210 and MATH 5211 (i.e., a year of abstract algebra).
Recommended Preparation: A semester of Algebraic Number Theory, and a semester of Algebraic Geometry.
Credits: 3
Meets: Tuesdays, and Thursdays, 1112:15, via WebEx call (registered participants will get link by email). Videos will then be posted to YouTube.
About the Instructor: Álvaro LozanoRobledo
I’m a Professor of mathematics at the University of Connecticut and the Director of Undergraduate Studies in the Department of Mathematics.
Office hours: TBA.
About the Book and Other Resources
I will be following the main reference: Joseph H. Silverman, “The Arithmetic of Elliptic Curves,” Springer, 2nd Edition. However, there are other references that may be very useful.

H. Daniels and Á. LozanoRobledo, “What is… an elliptic curve?”, in the Notices of the American Mathematical Society, Vol 64, Issue 3, March 2017, pp. 241243.

J. H. Silverman, J. Tate, “Rational Points on Elliptic Curves,” Springer – this book is an elementary version of the main reference.

Á. LozanoRobledo, “Elliptic Curves, Modular Forms, and their LFunctions” is another elementary introduction to elliptic curves.

J. H. Silverman, “Advanced Topics in the Arithmetic of Elliptic Curves,” Springer.

J. S. Milne, “Elliptic Curves,” published by Kea Books – this book is freely available at Milne’s website.

N. Koblitz, “Introduction to Elliptic Curves and Modular Forms,” Springer.

J. Tate, “The arithmetic of elliptic curves,” Invent. Math. 23 (1974), 179206 – The main reference was heavily influenced by this key survey article.

D. Husemöller, “Elliptic Curves,” Second Edition, Springer.

L. Washington, “Elliptic Curves: Number Theory and Cryptography,” Second Edition (Discrete Mathematics and Its Applications) 2nd Edition, CRC Press.
 E. Brown and A. Rice, “Why Ellipses Are Not Elliptic Curves,” Math. Mag. 85 (2012), no. 3, 163–176 – For those interested in the history of elliptic curves.
During the course we will discuss computability aspects of the theory, so it is helpful for students to familiarize themselves with computer packages that can handle computations on elliptic curves:
 A list of videos intros to the LMFDB, Magma, and Sage/CoCalc.
 LMFDB: The Lfunctions and Modular Forms DataBase.
 MAGMA. There is an online calculator here.
 SageMath and CoCalc.
Homework
Homework sets will be posted here periodically. The sets are a small selection of problems that should help students in understanding the theory, but of course there are many other problems available in Silverman’s book that are also a great resource for the learner. This is a topics class, so the homework sets are not mandatory. I’ll be happy to look at sets if you want to send me your solutions, but in general I expect that if you are interested in the material, you will be trying the problems on your own and reaching out to me when you need help or hints. For the sake of the grade, though, I do expect that you will submit some problems during the course (at least one per problem set).. If you have difficulties, do not waste time — get help! Please come to office hours!
 Homework Set 1.
 Homework Set 2.
 Homework Set 3.
 Homework Set 4a.
 Homework Set 4b.
 Homework 5.
 Homework 6.
Zulip Channel
A Zulip channel has been created to discuss material from the MATH 5020 – The Arithmetic of Elliptic Curves class. The instructor will try to answer questions that come up in the channel, but may not be able to get to every question, so this channel has been created so that (mostly) students can discuss and answer each other’s questions. The users of the Zulip channel must abide by the rules of engagement of the channel.
In order to join the Zulip channel, visit the following page passwordprotected page. The password is the title of Section III.§4 of Silverman’s “The Arithmetic of Elliptic Curves” (the password is all lower case): join our Zulip.
Tentative Schedule
The videos of the lectures can be found (as they become available) in this YouTube playlist.
Lecture  Topics (links to videos)  Notes 
1  What is… an elliptic curve? An introduction  Slides from the talk. 
0  Class logistics and description of the course  Lecture 0 
1  Introduction to diophantine equations  Lecture 1 
2  Number Fields… VS … Elliptic Curves  Lecture 2 
3  Intro. to algebraic varieties and curves  Lecture 3 
4  Varieties, function fields, dimension (part 1), and singularities, morphisms (part 2) 
Lecture 4 
5  Order of vanishing (part 1), an example (part 2), and ramification (part 3) 
Lecture 5 
6  More on ramification (part 1) and divisors, and differentials (part 2) 
Lecture 6 
7  RiemannRoch, Hurwitz, Weierstrass models  Lecture 7 
8  Models of elliptic curves, discriminant and jinvariant (part 1), and the group law (part 2)  Lecture 8 
9  The (geometric) group law (part 1), and the (Picard) group law (part 2) 
Lecture 9 
10  Isogenies (part 1) and (part 2), and the dual isogeny (part 3)  Lecture 10 
11  The Tate module.  Lecture 11 
(Optional lecture on adelic Galois representations)  Slides  
12  The Weil pairing (construction) and (properties)  Lecture 12 
13  Consequences of the Weil pairing (part 1), and elliptic curves over finite fields (Hasse’s bound, part 2)  Lecture 13 
14  An example of an elliptic curve over a finite field (part 1), and elliptic curves over C (part 2)  Lecture 14 
15  An introduction to the formal group of an elliptic curve.  Lecture 15 
16  Formal groups, homomorphisms (part 1), groups associated to formal groups, the formal logarithm, and formal exponential (part 2).  Lecture 16 
Happy Pi Day! (Extra lecture about pi and elliptic curves.)  Pi Day  
17  Torsion points in the groups associated to formal groups over DVR’s (part 1), and local fields, minimal models (part 2)  Lecture 17 
18  Elliptic curves over local fields: the fundamental exact sequence (part 1), and points of finite order over local fields: an example (part 2).  Lecture 18 
19  More on points of finite order (part 1), and the action of inertia (part 2)  Lecture 19 
20  Criterion of NéronOggShafarevich, and good and bad reduction (part 1), potential good reduction and the jinvariant (part 2), and the group E/E_0 (part 3).  Lecture 20
and a bit more 
21  The weak Mordell–Weil theorem: the Kummer pairing  Lecture 21 
22  Properties of the Kummer pairing (part 1) and the finiteness of the maximal abelian extension of exponent m unramified outside a finite set of primes (part 2)  Lecture 22 
23  The proof of the weak MordellWeil theorem (part 1), the descent procedure and heights of elliptic curves (part 2)  Lecture 23 
24  Torsion points (NagellLutz) (part 1), and the canonical height (part 2)  Lecture 24 
25  The canonical height pairing, and Zlinear independence of rational points (part 1); computing the MordellWeil group (part 2)  Lecture 25 
(Extra lectures) An introduction to group (and Galois) cohomology (part 1) and (part 2)  Cohomology notes  
26  Complete 2descent (part 1), and an example (part 2).  Lecture 26 
27  Example of 2descent (part 1), and definitions of Selmer and Sha (part 2)  Lecture 27 
28  Selmer and Sha: the fundamental sequence (part 1), twists, homogeneous spaces, and descent (part 2), and an example of descent via 2isogeny (part 3).  Lecture 28 
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