Character Theory of Finite Groups SS 2022


Schedule


Lecture: Mondays 10:00 - 11:30 Room 48-538 Lecturer: Jun.-Prof. Dr. Caroline Lassueur
Exercises: Fridays 12:00 - 13:30 Room 48-438 Instructor: Jun.-Prof. Dr. Caroline Lassueur
Office hour: Upon request

Link to the live stream of the FB Mathematik: http://stream.mathematik.uni-kl.de/live/
(Username/password: are the standard ones)

Public holidays / Exceptional schedule:
  • 6th of June 2022: Pentecost Monday - no lecture

Office hours: you can make appointments with me for individual qusetion sessions.

Exam Dates:
    Own Exam dates:
    • 4th of Aug 2022 (all day, starting 8am, Registration: Frau Sternike)
    • 29th of Sept 2022 (all day, starting 11am, Registration: Frau Sternike)
    • 21st of Oct 2022 (all day, starting 8am, Registration: Frau Sternike)
    Character Theory + Plane Algebraic Curves (with M. Schulze)
    • 1st of Sept 2022 (all day, starting 8am, Registration: Frau Dietz)
    • 29th of Sept 2022 (all day, starting 11am, Registration: Frau Sternike)
    • 21st of Oct 2022 (all day, starting 8am, Registration: Frau Sternike)
    Character Theory + Quadratic Number Fields (with C. Fieker)
    • 29th of Sept 2022 (all day, starting 8am, Registration: Frau Dietz)
    Character Theory + p-Adic Numbers (with G. Malle)
    • upon arrangement (Registration: Frau Sternike)


Updates


  • 2nd of May: The live stream of the FB Mathematik does not work at the moment. The lecture will be streamed over BBB in OpenOLAT as long as the latter does not work.
  • April 2022: please register in the URM system by Friday, the 29th of April, midday.

Lecture Notes


\(LaTeX\)ed lecture notes will be uploaded here every week before the lecture.

I will essentially follow my lecture notes from the SS 2020, but there will be changes!
Please, do use the updated version!

Lecture Notes: Full text until Week 14

Exercises


The Exercise Classes take place fortnightly. They begin in the 2nd week of the lecture period and then take place every second week.



Handing in solutions: From Sheet 1 on, each fortnight, there is one exercise to hand in. (However, all exercises you would like to have corrected can be handed in!) You should hand in your solutions in handwritten form by the due date. No LaTeXed solutions accepted.
You can hand in your solutions in German/English/French/Italian.

Complete solutions to the exerices to hand in are uploaded In OpenOLAT after the corresponding deadline.

Übungsscheine


You obtain an "Übungsschein" if the following criteria are fulfilled:
  • you have obtained at least 2 points out of 8 on the exercise to be handed-in in 6 Sheets out of 7;
  • you have actively taken part to the exercise classes: attendance to the exercise classes + presenting at least two solutions on the board during the semester.


References


Textbooks:
  • [JL01] G. James and M. Liebeck, Representations and characters of groups. See [zbMATH].
  • [Ser77] J.-P. Serre, Linear representations of finite groups. See [zbMATH].
    The original text is:
    [Ser98] J.-P. Serre, Représentations linéaires des groupes finis. See [zbMATH].
  • [Isa06] M. Isaacs, Character theory of finite groups. See [zbMATH].
  • [Web16] P. Webb, A course in finite group representation theory. See [zbMATH].
  • [CCNPW85] J.H. Conway, R.T. Curtis, S.P. Norton, R. Parker, R.A. Wilson, Atlas of Finite Groups. Clarendon Press, Oxford, 1985.
As a complement to my lecture notes, I strongly recommend Peter Webb's book, whose pre-print version is available at his webpage.

Oral Exam


In principle one should be able to explain the content of the lecture.
  • Definitions, statements of the theorems/propositions/lemmata should be known.
  • You should be able to explain short proofs as well as the main arguments of the longer proofs.
  • The Exercises mentioned in the lecture are important for the understanding of the theory.
  • There won't be any direct questions on the content of the Appendices.
  • you should also be able to give concrete examples/counter-examples to illustrate the results.
  • There will also be questions on concrete examples.
  • Also be ready to write down formally the concepts and results you are explaining.


Contents of the Lecture


  • Linear representations and characters
  • Modules over the group algebra
  • Character tables, orthogonality relations
  • Burnside's \(p^aq^b\)-theorem
  • Restriction, induction, inflation, tensor products
  • Clifford theory
  • Frobenius groups (if time permits)

Prerequisites: elementary group theory and linear algebra


Workload


Lecture : 2 SWS, i.e. 30 contact hours
Exercises : 1 SWS, i.e. 15 contact hours


Further Documents