Patrick Lei

Toric Varieties (Fall 2023)

References include:

About this seminar

Toric varieties are special geometric objects which are defined using combinatorial information. This combinatorial data can be used to compute many geometric properties of toric varieties. Even though toric varieties are quite special, many general phenomena can be observed on them. In this semester, we will discuss the basic geometry of toric varieties and then see their applications in algebraic geometry and other areas of mathematics. For example, applications of toric varieties to results in combinatorics are discussed in Chapter 5 of [F] and in Chapter 4 of [O].

Expectations

Each participant will give at least one talk over the course of the semester, during which I hope you enjoy some interesting mathematics and improve your presentation skills. Speakers are required to meet with me once at least 24 hours before your talk, at which point you should give me a title and abstract. After your talk, please email me a copy of your notes. When you are not speaking, I hope that you can help form a friendly and lively seminar environment. The expectations are as follows:

Outline of the seminar

Fundamental topics:

More advanced topics you may choose to talk about if you are interested, listed roughly in order of increasing difficulty. Note that some of these will take several talks. You can also choose a topic not on this list if you want.

Schedule

Each talk will last approximately 50 minutes. The schedule is subject to change at any point.

9/13
Patrick Lei
Crash course on algebraic varieties
I will tell you about algebraic varieties, rings, semigroups, and various other notions we will need for this seminar. We will also do organizational stuff.
Notes
9/20
Charlotte Coats
Rational polyhedral cones
Thomas Bueler-Faudree
Affine toric varieties
Notes
9/27
Charlotte Coats
Rational polyhedral cones
Notes
Rahul Ram
Fans and general toric varieties
Notes
10/4
Peng Liu
Toric varieties from polytopes
Notes
William Durie
Local properties
Notes
10/11
Patrick Lei
Crash course 2
Notes
Jane Meenaghan
Toric surfaces
Notes
10/18
Casey Qi
1-parameter subgroups, limit points
Notes
Jake Bernstein
Smooth toric surfaces
Notes
10/25
Kevin Hernandez
Toric resolution of surface singularities
Notes
Jennifer Luo
Toric resolution of singularities
Notes
11/1
No Seminar
11/8
Lilah Li
Orbits
Notes
Rahul Ram
Divisors
Notes
11/15
Peng Liu
Line bundles 1
Notes
Jake Bernstein
Line bundles 2
Notes
11/22
No Seminar (Thanksgiving)
11/29
Henny Kim
Moment map and the polytope
Notes
Jennifer Luo
Reflexive polytopes and Fano toric varieties
Notes
12/6
Patrick Lei
Reflexive polytopes and mirror symmetry
I will explain an application of reflexive polytopes and Fano toric varieties to mathematical physics.
Reference: Cox, Batyrev
Notes