Mathematics Colloquium

SPEAKER: Prof. Remus Nicoara

TITLE: Subfactors and their symmetries

ABSTRACT: The theory of subfactors was initiated by V. Jones in the eighties, as a Galois theory for inclusions of von Neumann algebras. Subfactors can be used to capture the symmetries of various mathematical and physical objects. Part of this structure can be uncovered by computing the standard invariant of the subfactor. This is a group-like object naturally associated to the subfactor, consisting in a lattice of inclusions of finite dimensional matrix algebras. We discuss various finiteness results for standard invariants, which also lead to new constructions of subfactors. Applications to the theory of Hopf algebras and the classification of complex Hadamard matrices will also be presented.

Refreshments will be available at 3:15 p.m.