| Speaker: Prof. Markus Haase Affiliation: University of Kiel Time: 11:00 Wednesday, 18 December, 2019 Location: 303-257 |
| Theorems assuring the strong convergence of a positive operator semigroup on a Banach lattice have a long tradition. One of the most intriguing instances is Greiner's theorem (1981) about semigroups (on Lp-spaces) containing a kernel operator. With its original proof being rather enigmatic, the theorem remained rather singular until it experienced a renaissance and some far-reaching generalizations in the new millennium, among others by Jochen Glück. Recently, Jochen and myself were able to integrate this and other theorems into a conceptual framework built on an analysis of the so-called "semigroup at infinity". I shall report on these findings, which consists in a beautiful combination of the Jacobs-deLeeuw-Glicksberg splitting theory with a structure theorem on positive representations of compact groups on atomic Banach lattices. |