#### Professor Oldřich Kowalski passed away

AbstractThis paper is dedicated to the memory of Professor Kowalski who was one of the leading researchers in the field of differential geometry and especially Riemannian and affine geometry. He significantly contributed to raising the level of teaching differential geometry by careful and systematic preparation of lectures for students. Prof. Kowalski is the author or co-author of more than 170 professional articles in internationally recognized journals, two monographs, text books for students. Prof. Kowalski collaborated with many mathematicians from other countries, particularly from Belgium, Italy, Japan, Romania, Russia, Morocco, Spain and others. With the death of Professor Oldřich Kowalský mathematical community are losing a significant personality and an exceptional colleague, a kind and dedicated teacher, a man of high moral qualities.