International
Mathematical research and teaching is an international endeavour. This is a great privilege for us mathematicians and I am happy that I had the opportunity to write papers with colleagues from many countries and 4 continents.Cooperation projects
funded by the DAAD "Dirichlet Forms, Operator Theory and Mathematical Physics" jointly with Ali Ben Amor (Gabes);see for workshops and schools organized in that project. Strategic partnership between the AIMS-NEI initiative and TU Chemnitz