Geoffrey Vooys

Memorial University of Newfoundland

Atlantic Association for Research in the Mathematical Sciences

CRG "Groups, Rings, Lie and Hopf Algebras"

Atlantic Algebra Centre


Equivariant Derived Categories


Mini course by Geoffrey Vooys

Dalhousie University

April 25 - 29, 2022


Picture of Geoffrey Vooys


The equivariant derived category is an important object of study in algebraic geometry, representation theory, the Langlands programme, and even in algebraic topology. It provides a natural place to study and perform calculations involving equivariant sheaves, equivariant local systems, equivariant perverse sheaves, and their cohomologies. However, while a very useful object, the equivariant derived category is an intimidating object to build and describe. In this mini-course I will introduce the background material necessary to be able to build this category and understand all the ingredients that go into its description. Of particular note is that I will give a quick introduction to sheaves and schemes with a focus on intuition, to avoid getting lost in the details of algebraic geometry.

The mini course will be held from April 25 to April 29, 2022 at Dalhousie University in Halifax, Nova Scotia. It will consist of five lectures, which take place in Room 227 of the Chase building at the following times in the Atlantic time zone:

  • Monday, April 25, 9:30-11:00 am
  • Tuesday, April 26, 1:30-3:00 pm
  • Wednesday, April 27, 1:30-3:00 pm
  • Thursday, April 28, 1:00-2:30 pm
  • Friday, April 29, 1:30-3:00 pm

Please note the slightly earlier starting time on Thursday.

To enable wide participation, it will be given in a hybrid format, i.e., the lectures will be presented to the audience in the lecture hall while being simultaneously broadcast over the internet. The corresponding login information is available upon request.

The mini course is jointly organised by the AARMS Collaborative Research Group “Groups, Rings, Lie and Hopf Algebras” and the Atlantic Algebra Centre. For further information, please contact Yorck Sommerhäuser at

Mini Course Materials

Recording of Lecture 1

Recording of Lecture 2

Recording of Lecture 3

Recording of Lecture 4

Recording of Lecture 5


Moreover, an expanded version of the lecture notes is now available, which also treats the material of the Wednesday lecture. Further expanded versions that cover even more additional parts will be posted here later.