On Thursday, 23.4.26, 10 AM, Ross 70.

Yair Glasner (BGU)

Will speak on:


Title: Nonabelian factors of an irrational rotation. 


Abstract: A joint work with Tattwamasi Amrutam and Eli Glasner. Let X = \mathbb{R}/2 \pi \mathbb{Z} and T:X \rightarrow X be an irrational rotation. From an operator algebra point of view the flow (X,T) is encoded by the C^* reduced crossed product C(X) \rtimes_r \mathbb{Z}. Factors of the dynamical system \times_n:X \rightarrow X give rise to intermediate algebras of the form C^{*}_{r} (\mathbb{Z}) < \mathcal{A} < C(X) \rtimes_r \mathbb{Z}. We develop a rich structure theory of such intermediate algebras, many of which do not come from dynamical factors as above.