# Group Theory Seminar

The Group Theory Seminar meets in room B129 of Van Vleck Hall on Tuesdays at 4pm.

For more information, contact Nigel Boston.

## Contents

## Fall 2012

date | speaker | title | host(s) |
---|---|---|---|

September 4 | |||

September 11 | |||

September 18 | |||

September 25 | Don Passman (Wisconsin) | local | |

October 2 | Don Passman (Wisconsin) | local | |

October 9 | Don Passman (Wisconsin) | local | |

October 16 | Marty Isaacs (Wisconsin) | local | |

October 23 | Marty Isaacs (Wisconsin) | local | |

October 30 | Marty Isaacs (Wisconsin) | local | |

November 6 | Sara Jensen (Wisconsin) | local | |

November 13 | Sarah Rich (Wisconsin) | local | |

November 20 (week of Thanksgiving) | Sarah Rich (Wisconsin) | local | |

November 27 | Owen Sizemore (Wisconsin) | local | |

December 4 | |||

December 11 | Owen Sizemore (Wisconsin) | local |

## Fall Abstracts

### Don Passman

*Group Rings*

These three talks will be an introduction to group rings.

### Owen Sizemore

*Amenability and Dixmier's Problem*

This talk will focus on the representation theory of amenable groups. We will begin by giving another characterization of amenable groups in terms of its unitary representations. We will then broaden our scope to look at more arbitrary bounded representations of amenable groups and ask if this gives us additional information about the groups. We will conclude will a proof of the Day/Dixmier result which essentially gives an answer of "no" to the previous question. In subsequent talks we will then look at the same question for nonamenable groups.

*Amenability and Dixmier's Problem (II)*

In this talk I will prove the Day/Dixmier result showing that all representation of amenable groups are unitarizable. I will then discuss what is known regarding the question of whether this characterizes amenable groups. Time permitting, I will talk about some recent progress and mention connections with random subgroups and ergodic theory.

## Spring 2013

date | speaker | title | host(s) |
---|---|---|---|

January 22 | |||

January 29 | |||

February 5 | |||

February 12 | |||

February 19 | |||

February 26 | |||

March 5 | |||

March 12 | |||

March 19 | |||

Spring Break | |||

April 2 | |||

April 9 | |||

April 16 | |||

April 23 | |||

April 30 | |||

May 7 |