The last time I saw Paul Erdős was in May 1995, during the Conference on Analytic Theory held in Urbana, Ill. in honour of H. Halberstam. It was a beautiful spring day, and we were walking (slowly, as Erdős had some trouble with his foot) in the park of Allerton Conference Center, where the meeting took place. At one point Erdős turned to me and said: ”You know, it is said that that those who p...