My biggest thanks goes to my mathematics teacher Franz Hagen (PhD), who accompanied me at the high school (Gymnasium) in Oer-Erkenschwick from 9th to 13th grade (Abitur). He was the one who taught me the joy of mathematics and recognized something like a talent. I dedicate this internet presence to him.

I thank the many mathematicians around the world who were kind enough to answer my questions, to critique my texts and ideas, or to help me in any other way. I would like to mention the following persons in alphabetical order.