INTRODUCTION TO REPRESENTATION THEORY- Spring 2026

Instructor:  SEMRA ÖZTÜRK

  

Office : M 138,  sozkap@metu.edu.tr,  For my schedule see http://users.metu.edu.tr/sozkap/aa.pdf

 

Grading :  Updated Feb 13, 2026

Mid Term Exam 40 pts April 18, at 12:00,  Final Exam 40 pts,  10 pts attendance, 10 pts hw ; Total 100.

Policies : Lecture attendance is required unless there is an overlapping course you are taking, in case of (verified) course overlaps this will not be a problem. 

Objectives:  At the end of this course, the student will learn: basic concepts used in representation theory, such as modules,  decomposing modules into irreducibles, computing character tables,  obtaining information about the group from the character table of the group .

Learning Outcomes:  Student, who passed the course satisfactorily will be able to: construct modules over group algebras, determine the type of the group algebra,  deteremine irreducibility of a given module compute the  character table of a group,  derive information about the group from its character table.

Text book : Representations and Characters of Groups, by G. James and M. Liebeck, Cambridge University Press 

 

Useful Sources

1.      Algebras and Representation Theory By Erdmann and Holmsen  https://link.springer.com/content/pdf/10.1007/978-3-319-91998-0.pdf

2.     Rings Modules and Linear algebra by Strickland modules.pdf

Tentative Syllabus including suggested problems from the Textbook:

Week

Topic

Relevant Reading

Suggested problems

1

Introduction, review of some topics:  Groups, subgroup lattices,   linear transformations

Chapter 1,

Chapter 1,  # 2, 4,7,10

Chapter 2,  # 5 (b), 7,9

2

Group Representations, FG-modules

Chapter 3, and 4

Chapter 3,  # 1,2,7,8

3

Submodules, permutation modules

Chapter 4, and 5

Chapter 4,  # 2,3,4.

4

FG-modules and irreducibility

Chapter 5

Chapter 5,  # 1,3

5

Group algebras and FG-homomorphisms

Chapter 6, 7 

Chapter 6,  # 1, 4,

Chapter 7,  # 1, 3

6

Maschke's Theorem, Schur's Lemma

Chapter 8, and 9

Chapter 8,  # 3,5,

Chapter 9,  # 4,5,6

7

Irreducible modules and group algebra

Chapter 10, and 11

Chapter 10, # 1,2,3,4,6

8

More on group algebra, conjugacy classes, Characters

Chapter 11, 12, 13

Chapter 13, # 1,2,3, 7,8,10

9

Inner product of characters

Chapter 14

Chapter 14, # 1,2,3,4,7,8

10

Inner products of characters, decomposition of modules, idempotent decomposition

Chapter 14

Chapter 14,  # 25--28

11

The number of irreducible characters

Chapter 15

Chapter 15,  #1,2,3,4

   12

Character tables and orthogonality relations

Chapter 16

Chapter 16,  #1,2,3,4

13-15

Some elementary character table, Normal subgroups and lifted characters

Chapter 18, 17

Chapter 17,  #1,3,4,5,