# Unit information: Representation Theory in 2020/21

Unit name Representation Theory MATHM4600 20 M/7 Teaching Block 1 (weeks 1 - 12) Dr. Tim Burness Not open MATH21100 Linear Algebra 2 and MATH33300 Group Theory None School of Mathematics Faculty of Science

## Description

Unit Aims

To develop the basic theory of linear representations of groups, especially of finite groups over the complex numbers. To develop techniques for constructing characters and character tables. To explore applications of the theory.

Unit Description

Representation theory studies the linear actions of a group G on a vector space V defined over a field. By fixing a basis for V, such an action yields a map from G to a group of invertible matrices, so we can "represent" the elements of G in a very concrete form. Moreover, this viewpoint allows us to apply techniques and tools from linear algebra to study groups, and this turns out to be a very powerful idea.

In this course, we will develop the basic theory of linear representations of groups, with a particular focus on finite groups and representations defined over the complex numbers. We will also introduce the theory of characters as a tool for studying representations and we will develop techniques for constructing characters and character tables. We will also describe some important applications of the theory, including Burnside's famous theorem on the solubility of finite groups of order p^aq^b.

Relation to Other Units

This is one of three Level 7 units which develop abstract algebra in various directions. The others are Galois Theory and Algebraic Topology.

## Intended learning outcomes

Learning Objectives

After taking this unit, students should:

• know the standard general properties of the character table of a finite group, and have an understanding of why these properties hold.
• be able to apply a variety of methods for constructing characters.
• be able to deduce properties of a group from its character table.

Transferable Skills

The application of abstract ideas to concrete calculations. The ability to tackle problems by making a sensible choice from among a variety of available techniques.

## Teaching details

The unit will be taught through a combination of

• synchronous online and, if subsequently possible, face-to-face lectures
• asynchronous online materials, including narrated presentations and worked examples
• guided asynchronous independent activities such as problem sheets and/or other exercises
• synchronous weekly group problem/example classes, workshops and/or tutorials
• synchronous weekly group tutorials
• synchronous weekly office hours

## Assessment Details

90% Examination 10% Coursework

Raw scores on the examinations will be determined according to the marking scheme written on the examination paper. The marking scheme, indicating the maximum score per question, is a guide to the relative weighting of the questions. Raw scores are moderated as described in the Undergraduate Handbook.

If you fail this unit and are required to resit, reassessment is by a written examination in the August/September Resit and Supplementary exam period.