Dr Hubert Przybycień visited the Chair of Approximation Theory of the Institute of Mathematics of Jagiellonian University from 2006-12-12 to 2006-12-13, where he held the lecture concerning subtraction in semigroups.
Prof. Ryszard Urbański took part in the 21th European Conference on Operational Research in Reykjavík (Iceland) from 2006-06-30 to 2006-07-10.
Dr hab. Dariusz Bugajewski visits the Howard University and the Morgan State University in Baltimore (USA) from 2006-05-06 to 2006-05-15, where he holds lectures and conducts research.