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Expanders and Their Generalisations

David Conion

Date Icon Week 3, Tuesday 29 January HT 2019
Time Icon 8:00pm

An expander is a sparse graph with the property that every small vertex subset expands, that is, is adjacent to many vertices outside of that set. The study of expanders has occupied a central place in both mathematics and computer science for over forty years, finding numerous applications across both areas. In recent years, a theory of high-dimensional, or hypergraph, expanders has begun to emerge and there is reason to believe that it will be every bit as fascinating and fruitful as the graph case. In this talk, I will try to introduce a few of the ideas in this new and exciting area.