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Greg Kuperberg

Mapping class group actions and intractable topological invariants
Vendredi, 24 Mai, 2019 - 10:30
Résumé : 

The question of determining the closed image of a quantum representation of a mapping class group began with an irreducibility result of Roberts. Then Freedman, Larsen, and Wang showed that the Jones braid group representations are usually dense in the target unitary group. Their influential work (also with Kitaev) also described an important motivation from quantum computing. I will describe later and continuing results, yielding irreducibility and denseness in the quantum case and surjectivity in the classical case, and the corollary that many natural topological invariants of knots and 3-manifolds are computationally intractable.

Institution de l'orateur : 
UC Davis
Thème de recherche : 
Topologie
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