INTRODUCTION TO REPRESENTATION THEORY- Spring 2025 

Instructor:  SEMRA ÖZTÜRK

Please check this page often  for further announcements this week, and come to lectures, we will start from the beginning on Tuesday, Feb 25 at 12:40.

 

NEW!! Updated  Feb 21 at  20:00

Math 464 is very likely to survive J

Today there were 5 students in class,  they requested to move  Wednesday 12:40 lecture to Friday 16:40.  

 

The proposed exam dates are :  April 5, and May 10 at 10:00

 

1)     If you are interested in the course (and satisfy the prerequisite)  please add this course when the registration system is active  and get approval as soon as possible. There is no need to send me e-mail. Just add the course.

 

2)    To see if there are overlapping for students who interested in the course but  were not in class today,  I ask ALL students who will register to vote in the new short poll below for a likely new schedule:

Tuesday

12:40

13:30

M105

Friday

15:40

17:30

M105

 

https://docs.google.com/forms/d/e/1FAIpQLSeE3sH4KUPZc1aZb_44BnNTLkjTB4p6cDuGIFsfCYg1vjF4Gw/viewform?usp=header

 

----------------------------------------------------------------------

Updated  Feb 19 at  14:00

According to the poll the schedule in the registration system should be  the schedule for the course if there are no new students next week.

Schedule :

Tuesday

12:40

13:30

M105

Wednesday

12:40

13:30

M105

Friday

15:40

16:30

M105

Please attend the lectures, we started today with two students only!

(Tuesday and Wednesday there is no overlap, for friday there are  overlaps with two courses but I must ignore that. So the sechedule is fixed now if all the studentswho voted in the poll register .)  For all of us to know the course is not closed, you should register as early as possible, and get the approval as soon as possible.

 

 Update Feb 18

If you want to add this course (and  stisfy the prerequisite)  please

 

1)    fill in the form below for schedule arrangement

https://docs.google.com/forms/d/e/1FAIpQLSfFm7XCae0pPn7JwzJAt-5GARHrbIkXN275KjOtYViV5uJJcQ/viewform?usp=header

2)    come  to the lectures according to the schedule in the registration system (which is updated on Feb 18). 

3)    write an email to sozkap@metu.edu.tr  if you have not done earlier stating your interest

4)    add this course next week when the registration system is active

     

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

 

Grading :  Exam 1 60pts,  Exam 2 60pts,  Final Exam 60,  20 pts attendance /hw ??

 Total 200.

Policies : Lecture attendance is required unless there is an overlapping course you are taking, in case of 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 

Tentative Weekly  :

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,