# Unit information: Algebra 2 in 2021/22

Unit name Algebra 2 MATH21800 20 I/5 Teaching Block 2 (weeks 13 - 24) Professor. Tim Dokchitser Not open MATH11005 Linear Algebra and Geometry and MATH10010 Introduction to Proofs and Group Theory None School of Mathematics Faculty of Science

## Description

Unit Aims

To develop the theory of commutative rings, and to apply it to solving problems concerning the factorisation of polynomials, algebraic numbers, ruler-and-compass constructions, and the construction of roots of polynomials.

Unit Description

Algebraic structures -- such as groups, rings, and fields -- are prevasive in mathematics. This course focuses on (commutative) rings, which are sets equipped with two (commutative) operations (called addition and multiplication), and that contain an additive identity and an additive inverse for each element of the set. A fundamental example of a ring is Z, the set of integers; other important examples include Q, Z modulo n, and Q[X], which is the set of polynomials in X with rational coefficients. A fruitful way to study rings and their properties is to study "homomorphisms" between rings: a homomorphism is a map that preserves addition and multiplication (just as a linear transformation preserves vector addition and scalar multiplication). Using homomorphisms and generalised modular arithmetic, we develop means of determining when a ring has additional nice properties, such as having multiplicitive inverses for each nonzero element of the ring. This is a very beautiful and clean theory; in proving the theorems, the students will learn some new techniques and strengthen their proof-writing skills.

Relation to Other Units

This unit has some relationship to (but is independent of), Linear Algebra 2 and the Level 7/M unit Representation Theory, and has a stronger relationship to Algebraic Number Theory and Galois Theory.

## Intended learning outcomes

Learning Objectives

After taking this unit, students should be able to state the basic definitions and results in the subject, to utilise the fundamental proof techniques, and to solve problems similar to those worked in the lectures and set as homework.

Transferable Skills

The ability to understand and apply general theory, and the acquisition of facility in calculating in a variety of number-systems.

## 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

85% Timed, open-book examination 15% 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.

## Resources

If this unit has a Resource List, you will normally find a link to it in the Blackboard area for the unit. Sometimes there will be a separate link for each weekly topic.

If you are unable to access a list through Blackboard, you can also find it via the Resource Lists homepage. Search for the list by the unit name or code (e.g. MATH21800).