Schemes 17: Finite, quasifinite
This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. We define finite morphisms, and attempt to sort out the three different definition of quasifinite morphisms in the literature.
From playlist Algebraic geometry II: Schemes
Schemes 16: Morphisms of finite type
This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. We introduce three properties of morphisms: quasicompact, finite type, and locally of finite type, and give a few examples.
From playlist Algebraic geometry II: Schemes
algebraic geometry 25 Morphisms of varieties
This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers the definition of a morphism of varieties and compares algebraic varieties with other types of locally ringed spaces.
From playlist Algebraic geometry I: Varieties
We give a buttload of definitions for morphisms on various categories of complexes. The derived category of an abelian category is a category whose objects are cochain complexes and whose morphisms I describe in this video.
From playlist Derived Categories
Weil conjectures 7: What is an etale morphism?
This talk explains what etale morphisms are in algebraic geometry. We first review etale morphisms in the usual topology of complex manifolds, where they are just local homeomorphism, and explain why this does not work in algebraic geometry. We give a provisional definition of etale morphi
From playlist Algebraic geometry: extra topics
algebraic geometry 24 Regular functions
This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers regular functions on affine and quasiprojective varieties.
From playlist Algebraic geometry I: Varieties
Fundamentals of Mathematics - Lecture 33: Dedekind's Definition of Infinite Sets are FInite Sets
https://www.uvm.edu/~tdupuy/logic/Math52-Fall2017.html
From playlist Fundamentals of Mathematics
algebraic geometry 26 Affine algebraic sets and commutative rings
This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers the relation between morphisms of affine algebraic sets and homomorphisms of commutative rings. As examples it describes some homomorphisms of commutative rings
From playlist Algebraic geometry I: Varieties
Jean Michel : Quasisemisimple classes
Abstract: This is a report on joint work with François Digne. Quasisemisimple elements are a generalisation of semisimple elements to disconnected reductive groups (or equivalently, to algebraic automorphisms of reductive groups). In the setting of reductive groups over an algebraically c
From playlist Lie Theory and Generalizations
This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. We define open and closed immersion, and give some basic properties and some examples.
From playlist Algebraic geometry II: Schemes
Charles Rezk - 1/4 Higher Topos Theory
Course at the school and conference “Toposes online” (24-30 June 2021): https://aroundtoposes.com/toposesonline/ Slides: https://aroundtoposes.com/wp-content/uploads/2021/07/RezkNotesToposesOnlinePart1.pdf In this series of lectures I will give an introduction to the concept of "infinity
From playlist Toposes online
Drinfeld's lemma for schemes - Kiran Kedlaya
Joint IAS/Princeton University Algebraic Geometry Seminar Topic: Drinfeld's lemma for schemes Speaker: Kiran Kedlaya Affiliation: University of California, San Diego; Visiting Professor, School of Mathematics Date: February 4, 2019 For more video please visit http://video.ias.edu
From playlist Joint IAS/PU Algebraic Geometry
Stefan Kebekus The geometry of singularities in the Minimal Model Program and applications to singul
This talk surveys recent results on the singularities of the Minimal Model Program and discusses applications to the study of varieties with trivial canonical class. The first part of the talk discusses an infinitesimal version of the classical decomposition theorem for varieties with vani
From playlist HIM Lectures: Junior Trimester Program "Algebraic Geometry"
Higher Algebra 5: Slices and filtered colimits
In this video, we provide further properties of the derived category of an abelian category. Along the way we discuss slice categories and filtered colimits. This is the fifth video in our introduction to ∞-categories and Higher Algebra. Feel free to post comments and questions at our pub
From playlist Higher Algebra
Equivariantization and de-equivariantization - Shotaro Makisumi
Geometric and Modular Representation Theory Seminar Topic: Equivariantization and de-equivariantization Speaker: Shotaro Makisumi Affiliation: Columbia University; Member, School of Mathematics Date: February 10, 2021 For more video please visit http://video.ias.edu
From playlist Seminar on Geometric and Modular Representation Theory
Schemes 10: Morphisms of affine schemes
This lecture is part of an online algebraic geometry course on schemes, based on chapter II of "Algebraic geometry" by Hartshorne. We try to define morphisms of schemes. The obvious definition as morphisms of ringed spaces fails as we show in an example. Instead we have to use the more su
From playlist Algebraic geometry II: Schemes
Danny Calegari: Big Mapping Class Groups - lecture 3
Part I - Theory : In the "theory" part of this mini-course, we will present recent objects and phenomena related to the study of big mapping class groups. In particular, we will define two faithful actions of some big mapping class groups. The first is an action by isometries on a Gromov-h
From playlist Topology