Social media brings out the best and the worst in people. He was rigorous yet open-minded, allowing people like me (who did some mathematical economics and finance) to cheat with inequalities by using the various canned methods for finding minima and maxima. He even tolerated computerized mathematics, provided of course there was some rigor in the process. I initially knew nothing about him but could observe rare attributes: an extraordinary amount of patience and a remarkable sense of humor. One summer, as he was in Israel, I informed him that I was vacationing in Lebanon. His answer: “Walking distance”. He always had a short comment that makes you smile, not laugh, which is a social art.
Alexander B. created a vibrant community around his Twitter account. He would pose a question, collect answers and patiently explain to people where they were wrong.
I, for myself, started almost every day with a puzzle, with the excitement of unpredictability, as it took from 5 minutes to 4 hours to complete –and it was usually impossible to tell from the outset. For a couple of years, it was the first thing I looked at with the morning coffee. There was some mild competition, mild enough to be entertaining but not too intense to resemble an academic rat race. Once someone got a proof, we had to look for another approach so…