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Next: MC260 Mathematical Statistics Up: Year 2 Previous: MC248 Further Real Analysis

MC249 Rings and modules


MC249 Rings and modules

Credits: 10 Convenor: Dr. R. Marsh Semester: 2


Prerequisites: essential: MC145, MC241
Assessment: Coursework: 20% One and a half hour exam: 80%

Lectures: 18 Classes: 6
Tutorials: 6 Private Study: 51
Labs: none Seminars: none
Project: none Other: none
Total: 75

Explanation of Pre-requisites

The definitions of a group and a ring together with the properties of polynomials are required from MC145. The concept of a vector space provides a motivational example of a module and, as such, elementary results from MC241 will be used when discussing this example.

Course Description

This course provides an introduction to the theory of rings and modules. Familiar examples of rings include the integers, the integers modulo n, rational numbers, real numbers, complex numbers, polynomials over a field, and $n\times n$ matrices over a field. The concept of a module has also been met before in the special cases of a vector space and an abelian group.

Much of the theory of commutative rings is motivated by the properties of the integers. This leads firstly to the idea of a Euclidean domain, which gives a general setting for the division algorithms already seen in MC145 for the integers and polynomials over a field, and secondly to the concept of a principal ideal domain, which gives particularly useful structure theorems for both rings and modules. Describing the structure of rings and modules is important in abstract algebra and enables us to apply this theory to many diverse areas of mathematics; from the examples listed above, it can be seen that the ideas in this course are used in number theory, linear algebra and group theory. The final part of this course considers some general theorems which allow us to describe the structure of any module.

Aims

The aim of this course is to introduce students to the basic structure and theory of rings and modules and to develop this theory to investigate principal ideal domains and the classification of any module as a homomorphic image of a free module. The parallels between number systems and other algebraic structures are drawn out in this course.

Objectives

To know the definitions of and understand the key concepts introduced in this module.

To understand and be able to use the main results and proofs of this course.

To be able to investigate the properties of a ring or module.

To relate the concept of an ideal to homomorphisms and factor rings.

To distinguish between the concepts of primeness and irreducibility.

To know the interrelationships between certain classes of rings.

To be aware of the unique factorisation properties motivated by the example of the integers.

To understand that every finitely generated module is a homomorphic image of a free module.

Transferable Skills

The development of understanding of the abstract method within ring theory.

The ability to apply taught principles and concepts to new situations.

The ability to present written arguments and solutions in a coherent and logical form.

The ability to use the techniques taught within the course to solve problems.

Syllabus

Ring, module, zero divisor, integral domain (ID), unit, division ring, quaternions, field, subring, submodule, ring (module) homomorphism, ideal, kernel, image, construction of ideals, principal ideal, example of a non-principal ideal and a one-sided ideal, ideals in Z, characterisation of a division ring as a ring with precisely two right ideals, coprime ideals, factor ring, factor module, isomorphism theorems.

Divisibility in an ID and its relation to principal ideals, associate, irreducible element, prime element, Z$[\sqrt{d}]$ and the norm function, Euclidean domain (ED), principal ideal domain (PID), every ED is a PID, to know that there are PIDs which are not EDs, every prime element in an ID is irreducible and the converse holds in a PID, Z[x] is not a PID, unique factorisation domain (UFD), to know that every PID is a UFD and that if R is a UFD then so is R[x], discussion of unique factorisation in Z, Z$[\sqrt{d}]$ and F[x] where F is a field.

Cyclic modules, characterisation of cyclic modules, finitely generated modules, direct sum construction for rings and modules, every finitely generated module is a homomorphic image of some Rn, free modules, every module is a homomorphic image of a free module.

Reading list

Recommended:

B. Hartley and T. Hawkes, Rings, Modules and Linear Algebra, Chapman and Hall.

Background:

J. B. Fraleigh, A First Course in Abstract Algebra, 5th edition, Addison-Wesley.

W. K. Nicholson, Introduction to Abstract Algebra, PWS-Kent.

Details of Assessment

There will be four pieces of work set for assessment which all carry equal weight and together count for 20% of the final mark.

There are four questions on the examination paper; all marks gained will be counted. All questions carry equal weight.


next up previous
Next: MC260 Mathematical Statistics Up: Year 2 Previous: MC248 Further Real Analysis
Roy L. Crole
10/22/1998