Data: piątek, 16.04.2021, 12:30-14:00
Prelegent: dr Marek Kaluba (WMI UAM & TU Berlin)
Abstrakt: I will gently introduce property (T) and relate it to the spectral gap of the group Laplacian. Then we will see how the existence of spectral gap can be translated to a positivity statement, which in turn could be turned into a sum of squares decomposition problem. Finally an order-based argument will be presented to derive the existence of an exact decomposition from an approximate one.
This is a first lecture in a series of three by dr Kaluba.