Recently a student of ours here in Trieste had a problem in logics which puzzled him. He decided to write directly to Jurij Matjasevic and got a prompt, polite, and informative answer. Now, Matjasevic is not simply a good mathematician, he is a mathematical myth, and so our reactions (of us the teachers) were: how lucky, this greenhorn, but how incredibly cheeky! Then I remembered that I had had a similar experience. I was preparing my final dissertation (which implies that all of this took place several decades ago) and during the summer I intended to go to Romania, the country to which my family (and myself) were so deeply linked with. I had relatives in Transylvania, and so to Cluj I went. I spoke with my mentor at Trieste University before leaving, because I had made a very odd choice for my dissertation: computational linguistics, a subject fully unknown in Trieste – but I liked languages and not only mathematics. Luckily my mentor was a curious person, and he knew very well how surprising and rich mathematics may be. So he told me: if you go to Cluj, there is a friend of mine there, maybe he may help you, and help me, too. I could speak a more than passable Romanian, and with professor Iulius Maurer we spoke Romanian rather than English. He invited me to one of his classes of algebra at Bolyai University, became Maurer Gyula, and gave all his class in Hungarian. Power of mathematics! What he wrote on the blackboard, all those symbols of algebra, allowed me at least to understand what the class was about. More important, he gave me three books and the author or coauthor of two of them was Solomon Marcus, the first time I heard the name. I was quite excited: one of the books was about algorithms (only Euclid’s algorithm was known to me then), but the other two, the two Marcus’ books, were about *Lingvistica matematică*, which meant that computational linguistics did exist and was not just Chomsky, the problem of my dissertation was brilliantly solved! A pity, Maurer told me, that you cannot go to Bucharest, because Marcus is an extraordinary mathematician. Back home, after having infected with the beauty of mathematical linguistics and Marcus’ books also a fellow student of mine, Oliviero Stock, I was contacted by a linguist about a problem of fuzzy classification of Romance languages, where a fuzzy generalization of the usual Hamming distance between binary strings was needed. I thought of Marcus, and wrote to him. I got a prompt, polite, and informative answer – actually we began a correspondence and I ended up publishing one of my first papers, the very first of which I am reasonably proud of even nowadays. I was still a greenhorn, of course, and of this Marcus was quite aware, because he read quite carefully everything I wrote. To some of the questions he posed to me I could not answer, some I did not even really understand. But Marcus was a gentleman, he never let me feel down, and even if some of his questions were left unanswered (and unanswered they remained for many years) at a certain point he told me: OK, publish it! […]

Trieste, February 2017