# Representation Theory (BM)

Course
2024-2025

Linear Algebra 1 and 2, Algebra 1, Algebra 2.

## Description

Representation theory is about understanding and exploiting symmetries using linear algebra.
The central objects of study are linear actions of groups on vector spaces. This gives rise to a
very structured and beautiful theory, which can be viewed as a generalisation of Fourier analysis
to a non-commutative setting. Representation theory plays a major role in mathematics and
physics. It provides a framework for understanding finite groups, special functions, and Lie groups
and algebras, and is the mathematical basis for the theory of elementary particles in physics.

## Course Objectives

After this course students will be able to:
1. Define and use basic concepts and tools from the theory of modules and from homological algebra.
2. Formulate and explain Wedderburn and Maschke’s theorems.
3. Give an overview of the basic theory of representations of finite groups.
4. Construct the character tables of many different finite groups.
5. Formulate and explain Burnside’s theorem.

## Timetable

You will find the timetables for all courses and degree programmes of Leiden University in the tool MyTimetable (login). Any teaching activities that you have sucessfully registered for in MyStudyMap will automatically be displayed in MyTimeTable. Any timetables that you add manually, will be saved and automatically displayed the next time you sign in.

MyTimetable allows you to integrate your timetable with your calendar apps such as Outlook, Google Calendar, Apple Calendar and other calendar apps on your smartphone. Any timetable changes will be automatically synced with your calendar. If you wish, you can also receive an email notification of the change. You can turn notifications on in ‘Settings’ (after login).

For more information, watch the video or go the the 'help-page' in MyTimetable. Please note: Joint Degree students Leiden/Delft have to merge their two different timetables into one. This video explains how to do this.

## Mode of instruction

Lectures, tutorials and assessed homework.

## Assessment method

Your final grade will consist of a combination of weekly homework assignments (considered as ‘practical = praktische oefening’), written final exam, and (possibly) a resit. The homework grade is the average of all weekly homework grades with the lowest two grades dropped. There is no retake for the homework.

Hendrik Lenstra: Representatietheorie, 2003. Lecture notes by Jeanine Daems and Willem Jan Palenstijn (in Dutch). There is an English translation by Gabriele Dalla Torre.

Serge Lang, Algebra. Springer--Verlag, 2002. (Chapter XVIII is about representation theory; book freely available through SpringerLink)

Jean--Pierre Serre, Linear Representations of Finite Groups. Springer New York, 1977. (Freely available through SpringerLink.)

William Fulton, Joe Harris, Representation Theory: A First Course. Springer New York, 2004. (Freely available through SpringerLink.)

## Registration

From the academic year 2022-2023 on every student has to register for courses with the new enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.

Please note that it is compulsory to both preregister and confirm your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course. Confirming your exam participation is possible until ten days before the exam.

Extensive FAQ's on MyStudymap can be found here.

## Contact

Yagna Dutta: y.dutta@math.leidenuniv.nl
Bart de Smit: b.de.smit@math.leidenuniv.nl