Dear Leo, I can still not believe that you are gone. Today again, while thinking about things I am currently working on, I had a question and my first thought was to discuss it with you. Similarly with some issues today in a lecture of our Mathematics course. You helped me with so many things, with your huge experience and great new ideas - but most importantly, you always had an open ear and always were so eager to help - and I know that I am not the only one who experienced this, but that this was true for anyone who approached you, be it colleagues or students. Now I come to realize that, to some extent, we failed to do the same for you and I feel very sad and sorry about this.
Working with you for the last two years was a great experience, I am very happy to have had that chance, and very sad that it did not last longer.