## Archive for the ‘Groups and Group Actions’ Category

### Groups and Group Actions: Lecture 3

February 22, 2017

In which we start to explore permutations.

### Groups and Group Actions: Lecture 2

February 16, 2017

In which we meet the dihedral groups, build new groups from old, and explore Cayley tables.

### Groups and Group Actions: Lecture 1

February 15, 2017

In which we learn what a group is, and meet many examples.

### Groups and Group Actions: Lecture 0

February 14, 2017

Welcome to the course blog for the Oxford first year Groups and Group Actions course (Hilary and Trinity Terms 2017).  I hope that this will be a useful resource to accompany the lectures, problems sheets and tutorials.  Please check back after each lecture for a new post.  In addition, I have a course page with some useful information, and you will also want to visit the official department course page (with problems sheets, for example).  My YouTube channel hedgehogmaths has some videos that you might find helpful when revising the course.

You are very welcome to leave comments (for me and for your fellow students) on each post.  For example, you might have your own suggestions for good places to read about the topics, or you might have another way to look at one of the ideas, or you might have a really good example that illustrates some interesting aspect of the material, or you might have a question that you’d like to raise.

Of course, now I have to suggest something to think about before Lecture 1!  So here it is.  If you haven’t come across a definition of a group before, then you could do some quick reading, for example this very accessible NRICH article.  How many examples of groups have you come across in the Oxford course so far?  (Hint: you’ve met lots!)  Think of as many as you can, it’s really helpful when learning group theory to have many examples of groups in mind.

### Groups and Group Actions: Lecture 16

May 18, 2016

In which we meet Cayley’s Theorem and reach the end of this particular adventure, but catch a glimpse of far-off lands still to be explored.

### Groups and Group Actions: Lecture 15

May 16, 2016

In which we meet the Orbit-Counting Formula

### Groups and Group Actions: Lecture 14

May 11, 2016

In which we explore groups of order $p^2$ and encounter Cauchy’s Theorem.

### Groups and Group Actions: Lecture 13

May 9, 2016

In which we explore the Orbit-Stabiliser Theorem.

### Groups and Group Actions: Lecture 12

May 4, 2016

In which we meet group actions.

### Groups and Group Actions: Lecture 11

May 2, 2016

In which we meet and explore quotient groups.