"Nachbarschaftstagungen" of the OeMG in Bozen, Italy, Sept. 22-26, 2003, together with SIMAI and UMI The Czech-Catalan meetings  2005 in Prague and 2006 in Barcelona Podbankse, Slovakia, Sept. 16-21, 2007, together with JSMF (http://www.mat.univie.ac.at/~oemg07/  ) The joint mathematical conference CSASC 2010 in Prague,  Czech Republik, Jan. 22-27, 2010 (http://cms.jcmf.cz/csasc/)