Seminario de Geometría Algebraica

Seminario de Geometría Algebraica
2025-04-03
13:30hrs.
Marcos Canedo. UC Chile
Baby: Deformaciones de Superficies Algebraicas y Obstrucciones
sala 2
2025-04-01
13:30hrs.
Yulieth Prieto. UC Chile
Automorphism Groups and Quotients
sala 2
Abstract:
Symplectic and non-symplectic. General properties of these automorphisms. Quotients of K3 surfaces by automorphisms of finite order. Applications of Torelli Theorem. Comments on the automorphism group for the Hilbert scheme of points on K3 surfaces. 
https://sites.google.com/view/yuliethprietom/teaching/seminario-puc?authuser=0
2025-03-27
13:30hrs.
Marcos Canedo. UC Chile
Baby: Superficies Singulares y No Singulares
sala 2
2025-03-25
13:30hrs.
Yulieth Prieto. UC Chile
Teorema de Torelli para superficies K3
sala 2
Abstract:
  • Torelli Theorem for K3 surfaces and its proof. Period map. Moduli of polarized K3 surfaces (the case of Kummer surfaces). Formulation of Torelli Theorem for IHS manifolds. 

2025-03-20
13:30hrs.
Marcos Canedo. UC Chile
Baby: Fracciones Continuas Negativas, Cadenas de Wahl, Fracciones del 0
sala 2
2025-03-18
13:30hrs.
Yulieth Prieto. UC Chile
K3 surfaces: definiciones y problemas
sala 2
Abstract:
K3 surfaces and their analogues in higher dimensions 

The goal of this seminar is to present the fundamental tools for formulating questions related to the study of specific geometric properties of K3 surfaces (e.g., such as automorphisms, elliptic fibrations, Shioda-Inose structures). Furthermore, it aims to explore the analogue of these tools in the context of higher-dimensional varieties, known as irreducible holomorphic symplectic (IHS) manifolds or Hyperkähler. 


https://sites.google.com/view/yuliethprietom/teaching/seminario-puc?authuser=0
2025-03-13
13:30hrs.
Giancarlo Urzúa. UC Chile
BABY: Fracciones continuas negativas en geometría birracional
sala 2
Abstract:
Será una introducción a geometría birracional de degeneraciones de superficies complejas, basado en el libro en progreso "Negative continued fractions in birational geometry: A guide to Wahl degenerations of surfaces". 

Tópicos guías:

 

1. Hirzebruch-Jung continued fractions

1.1. Basics

1.2. Wahl chains

1.3. Zero continued fractions

2. Singular and nonsingular algebraic surfaces 

2.1. Generalities on surfaces and singularities 

2.2. Cyclic quotient singularities 

2.3. T-singularities 

3. Deformations 

3.1. General basic theory for affine and proper varieties 

3.2. Q-Gorenstein deformations 

3.3. Kollár–Shepherd-Barron correspondence 

4. W-surfaces

4.1. Picard group, class group, and topology

4.2. MMP for W-surfaces I 

4.3. MMP for W-surfaces II 

5. N-resolutions

5.1. Existence and uniqueness 

5.2. Braid group action 

6. Exceptional collections of Hacking bundles 

6.1. Hacking exceptional bundles 

6.2. Hacking exceptional collections 

6.3. Exceptional collections and H.e.c.s 

 

2024-12-03
13:30hrs.
Jenia Tevelev. Umass Amherst
Deformations of the Kalck-Karmazyn Algebra via Homological Mirror Symmetry
sala 2
Abstract:
Kawamata observed that a Q-Gorenstein smoothing of a Wahl singularity gives rise to a matrix order, i.e., a 1-parameter flat degeneration of a matrix algebra. Tevelev and Urzúa later generalized this result to general smoothings of 2-dimensional cyclic quotient singularities. However, these results were proved using abstract methods of birational geometry, making explicit calculations challenging. In joint work with Yanki Lekili, we use homological mirror symmetry to derive explicit formulas for Kawamata’s matrix orders.
2024-11-26
13:30hrs.
Aníbal Aravena. UC Chile
Grand Finale: Superficies de K3 y Condiciones de Estabilidad
sala 2
2024-11-26
13:30hrs.
Aníbal Aravena. Umass Amherst
Fano visitor conjecture for K3 surfaces
sala 2
Abstract:
A smooth projective variety is said to be a Fano visitor if its derived category  can be embedded into the derived category of a smooth Fano manifold. In 2011, Bondal conjetured that every smooth projective variety is a Fano visitor. In this talk, I will discuss  a proof of this conjecture for  75% fo K3 surfaces  by using the work of Bayer and Macrì, which describes the birational geometry of a moduli space of sheaves on a K3 surface  through Bridgeland stability condition, and the study of fixed locus of antysimplectic involution by Saccà, Macrì, O'Grady, and Flapan. 
 
2024-11-21
13:30hrs.
Benjamín Maldonado. UC Chile
Baby Baby: Cocientes de Variedades Afines Por Grupos Finitos
sala 2
2024-11-19
13:30hrs.
Aníbal Aravena. Umass Amherst
Geometría Birracional de Espacios de Moduli
sala 2
2024-11-14
13:30hrs.
Francisca Paredes. UC Chile
Baby Baby: Transformaciones de Cremona
sala 2
2024-11-07
13:30hrs.
Camila Pérez. UC Chile
Baby Baby: 28 Rectas Bitangentes de Una Cuártica Plana
sala 2
2024-10-29
13:30hrs.
Aníbal Aravena. Umass Amherst
Haces Fibrados y Estabilidad
sala 2
2024-10-24
13:30hrs.
Benjamín Macías. UC Chile
Baby Baby: Superficie Elíptica de Un Pincel de Cúbicas
sala 2
2024-10-22
13:30hrs.
Aníbal Aravena. Umass Amherst
Estructura de Hodge y Teorema Global de Torelli, Classical, Derived and Twisted
sala edificio Villanueva de usos múltiples
2024-10-17
13:30hrs.
Giancarlo Urzúa. UC Chile
Baby Baby: Teorema de Pascal
sala 2
2024-10-15
13:30hrs.
Sebastián Torres. UC Chile
Superficies de K3 y condiciones de estabilidad: intro a las K3
sala 2
Abstract:
15 Oct: Superficies K3,  Cohomología e invariantes principales. Referencia: Lectures on K3 surfaces (Huybrechts). Chapter 1.1-1.3

22 Oct: Estructura de Hodge y Teorema Global de Torelli,  classical, derived and twisted (Huybrechts). Section 1.1.

29 Oct: Haces fibrados y estabilidad. Referencias: Lectures on K3 surfaces (Huybrechts). Chapter 9.1-9.3

05 Nov:  Estabilidad de Gieseker y espacios de moduli. Referencias: The geometry of Moduli space of sheaves (Huybrechts & Lehn) Chapter 1.2

12 Nov: Categorías derivadas y condiciones de estabilidad de Bridgeland, Referencia: Introduction to Bridgeland stability conditions (Huybrechts) & Stability conditions on K3 surfaces (Bridgeland)

19 Nov: Geometría birracional de espacios de moduli. Referencia: MMP via for moduli space of sheaves on  K3s via wall crossing: Nef and movable cone, Lagrangian fibrations (Bayer-Macri)

26 Nov:
2024-10-08
13:30hrs.
Mauricio Bustamante. UC Chile
Herramientas Topológicas Para Problemas en Superficies Algebraicas V
sala 2
https://www.mat.uc.cl/~urzua/