# Mathematics Colloquia and Seminars

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### 2-groups and their representations

**QMAP Seminar**

Speaker: | Derek Wise, UCD |

Location: | 2112 MSB |

Start time: | Thu, Jan 15 2009, 3:00PM |

A "2-group" is a category equipped with a multiplication satisfying laws like those of a group. Just as groups have representations on vector spaces, 2-groups have representations on "2-vector spaces", which are categories analogous to vector spaces. In this talk I will give an introduction to 2-groups and what they are good for, focusing on examples from topology and physics. I'll also explain 2-vector spaces, and begin describing 2-group representation theory. In a sequel I will explain this representation theory in more detail.

This talk is the first in a series, and will be based on arXiv:0812.4969