# MAGIC064: Algebraic Topology

## Course details

A core MAGIC course

### Semester

Spring 2012
Monday, January 16th to Friday, March 23rd

### Hours

Live lecture hours
20
Recorded lecture hours
0
0

Tuesdays
09:05 - 09:55
Thursdays
09:05 - 09:55

## Description

Algebraic topology studies `geometric' shapes, spaces and maps between them by algebraic means. An example of a space is a circle, or a doughnut-shaped figure, or a Möbius band. A little more precisely, the objects we want to study belong to a certain geometric `category' of topological spaces (the appropriate definition will be given in due course). This category is hard to study directly in all but the simplest cases. The objects involved could be multidimensional, or even have infinitely many dimensions and our everyday life intuition is of little help. To make any progress we consider a certain `algebraic' category and a `functor' or a `transformation' from the geometric category to the algebraic one. We say `algebraic category' because its objects have algebraic nature, like natural numbers, vector spaces, groups etc. This algebraic category is more under our control. The idea is to obtain information about geometric objects by studying their image under this functor. Now the basic problem of algebraic topology is to find a system of algebraic invariants of topological spaces which would be powerful enough to distinguish different shapes. On the other hand these invariants should be computable. Over the decades people have come up with lots of invariants of this sort. In this course we will consider the most basic, but in some sense, also the most important ones, the so-called homotopy and homology groups.

### Prerequisites

Algebra: Groups, rings, fields, homomorphisms, examples
Standard point-set topology: topological spaces, continuous maps, subspaces, product spaces, quotient spaces, examples

### Syllabus

Content:
Homotopy: fundamental group and covering spaces, sketch of higher homotopy groups.
Singular homology: construction, homotopy invariance, relationship with fundamental group.
Basic properties of cohomology (not excision or Mayer-Vietoris yet), motivated by singular cohomology.
Relative (co)homology.
Connecting homomorphisms and exact sequences.
Excision.
The Mayer-Vietoris sequence.
Betti numbers and the Euler characteristic.
Thom spaces and the Thom isomorphism theorem, Cohomology of projective spaces and projective bundles, Chern classes.
Relationship with existing courses:
The cohomology part is constructed from the current MAGIC011.

## Lecturer

• FN

### Dr Frank Neumann

University
University of Leicester

## Bibliography

### Follow the link for a book to take you to the relevant Google Book Search page

You may be able to preview the book there and see links to places where you can buy the book. There is also link marked 'Find this book in a library' - this sometimes works well, but not always - you will need to enter your location, but it will be saved after you do that for the first time.

## Assessment

The assessment for this course will be released on Monday 21st September 2020 and is due in by Friday 27th April 2012 at 23:59.

There will be a final exam at the end of the course to be marked with pass/fail. More details to be announced at later stage.

Please note that you are not registered for assessment on this course.