Eduard Ortega (Norwegian University of Science and Technology)
Thursday 26th March, 2020 15:00-16:00 Zoom
The notion of C*-unique Banach *-algebras was introduced in the 80's by Boidol, meaning that a Banach *-algebra accepts just one C*-norm. This concept was then specialize to the case of the Banach group algebras L^1(G), saying that a group is C*-unique if L^1(G) is C*-unique. An obvious necessary condition is amenability of the group, but turns out not to be sufficient, at least in the locally compact case. Applications of C*-uniqueness can be found in measure theory, in the so-called Pompeiu Problem, but also in Gabor analysis, since it was proved by Gröchening and Leinert that C*-uniqueness together with symmetry of the Banach algebra implies spectral invariance. In this talk I will talk about C*-uniqueness of the Banach *-algebra L^1(G) for an étale groupoid G, and give conditions for when it is C*-unique. Unless, the group case (topological) amenability it is no longer a necessary condition, but instead the weak containment property. This is a joint work with Are Austad.
Note: This is a webinar held via Zoom. Here are the details:
Meeting-ID: 386 504 521
Join via SIP