Let me add my condolences and shock to hear of Marek's death. I first met Marek in about 1986 -- I think he was a student in Warsaw at the time. I had been invited to talk at the Banach Center by Helena Rasiowa -- my connection to the formidable Helena was actually through her son Zbigniew Ras. Helena led an effort to keep Polish mathematicians and computer scientists in touch with their western counterparts despite being part of the soviet union ... often through invitations to the Banach Center. Needless to say I was very excited to travel behind the iron curtain. Helena had appointed a "chaperone" for me: being rather ignorant I assumed it might be a member of the communist party and a requirement for visitors. It was, however, Marek! Not at all communist! Helena knew I was interested in category theory and had paired me accordingly. At that time it was usual to get some local currency of the country before you travelled there: I recall going to the bank (in the US) and being told that there was "no exchange rate" for zloti. So when I arrived at the airport in Warsaw I naively had first in mind to get zloti. There was a booth to exchange money so I exchanged some dollars and got what I thought must be a very generous exchange rate. Marek met me at the gate and the first thing he said was "I hope you did not exchange any money! They give a terrible exchange rate!" ... I instantly knew that I could trust Marek! In fact, the Banach institute gave me a generous stipend in zloti and there was no need to exchange any money. Marek was an excellent host and introduced me to a Warsaw ... still behind the iron curtain. Lech Welesa was in prison at that time. The first experience of Soviet life (in winter) was to discover that the communal hot water did not work as pipes from the power station had burst (actually no one said what happened or even would admit that the system had broken). I recall Helena -- the realist -- making arrangements so that participants could have a bath in another quarter of the city. At the end of the meeting I still had a huge amount of zloti so Marek took me shopping. This was an interesting experience as it consisted of joining queues to find out what they were queuing for! Needless to say I could not spend all my zloti so I ended up giving them to Marek. I learned that university staff were not really paid a living wage so these perks (and visiting positions in the US -- often brokered by Helena) were essential. I was always delighted to see Marek at (Category Theory) conferences and will greatly miss him. -robin (Robin Cockett) ---------- You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. Leave group: https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.ashx?source=EscalatedMessage&action=leave&GuestId=6bf90c14-94d1-45b7-a0b5-9dd447734d27

I stand corrected and I certainly apologize if I caused offence ... my "dates" may well be as wrong as my "facts". This was a shocked reaction to the news and just my very impressionistic memories of my visit to Poland, what was happening at that time, and how I first met Marek! The "Polish People's republic" was, absolutely, an independent state (using zloti)! It was – from the west's perspective – "behind the iron curtain" but, oh dear, not Soviet. Most likely, I simply mixed up Solidarity being outlawed with Lech Welesa being in prison (oh dear!). Thank you for correcting me. While not being so happy about my insensitive blunders ... you also pointed out more brutally what repression could mean in Poland at that time. I just wished for it not to be forgotten what a different world that was -- hopefully not to be repeated -- and yet, also, how out of that world grew Marek with his smile. -robin ________________________________ From: Tadeusz Litak <tadeusz.litak@gmail.com> Sent: Wednesday, March 6, 2024 9:52 PM To: Robin Cockett <robin@ucalgary.ca>; Karol Szumiło <karol.szumilo@gmail.com>; categories@mq.edu.au <categories@mq.edu.au> Subject: Re: Marek Zawadowski I'd like to add to the condolences with my own recollection of Marek (and, less importantly, correct some mistaken claims in Robin's email). Ironically, I only met Marek after I left Poland for good, in Tbilisi 2003, at the first edition of the TANCL conference (later known as TACL, with "categories" replacing "non-classical logics" in the name). The first immediate impression was how youthful he was, in the best possible sense: both physically and intellectually, despite already being an accomplished researcher. Having heard that there were other Poles at the event (Tomasz Kowalski and me), he immediately descended upon our room, inquiring how many slides we had prepared, and whether we thought that the scorching heat outside would reach 40 degrees that day... Within less than a minute, you knew that this was somebody whose excellent intellect wouldn't get in the way of good fun and good companionship. And that worked splendidly at that conference. I also saw soon with admiration and relief that he was unwilling to respect artificial borders between fields. We should admit here that the relationships between category theorists and logicians were sometimes complicated, and as usual in such cases, both sides are probably to blame. But Marek was among those researchers who couldn't care less about any sectarian divisions. His joint book with Silvio Ghilardi on "Sheaves, Games and Model Completions" is a great expression of this spirit. Even very (apparently) inherently syntactic results turn out to allow duality-based proofs using their methods. While in the case of uniform interpolation for intuitionistic logic or Löb logic semantic proofs using less overtly categorical terminology were found independently by Albert Visser, the potential of their framework still needs to be fully explored. An excellent example was provided recently by Silvio Ghilardi and Luigi Santocanale, who showed how a (seemingly impenetrable) syntactic theorem by Wim Ruitenburg (JSL 1984) on finite order of intuitionistic formulas can be proved using methods of that book. But one cannot discuss this or anything else with Marek anymore. The only way left to learn from him now is by reading his papers. And ancient philosophers often suggested that this is an inferior method of learning from masters. Now for correcting Robin's claims:

Helena led an effort to keep Polish mathematicians and computer scientists in touch with their western counterparts despite being part of the soviet union

Let me point out that the Polish People's Republic, while certainly being an unfree, oppressive and poor country, equally certainly wasn't a part of the Soviet Union. Had it been the case, Robin, you would have been paid in rubles rather than in złotys, for example. The differences went deeper. Unlike the Soviet Union, the "Polish People's Republic" had powerful individual agriculture and Church not controlled by the state. An independent trade union like Solidarity, boasting at its 1980-81 peak more that a quarter of the entire population as its members, would have been downright impossible in the USSR. "The Eastern side of the Iron Curtain" and "The Soviet Union" were not equivalent notions, even if one could hardly speak about sovereignty either (can we speak about it these days?). I don't want to go too deeply into present-day politics, but perhaps this can explain the difference to you: presently, the Western world is militarily, economically and politically controlled from Washington. It still doesn't imply that Calgary or Warwick lie in the United States. Even though the language is the same (which isn't the case with Polish and Russian; in fact rather few Poles spoke fluent Russian even back then in 1986, despite the language being officially taught at schools...).

Lech Welesa was in prison at that time.

Actually, this also seems untrue, unless you got the date of your visit to Poland wrong by five years, and even then it wouldn't have been fully correct. In 1981-82, during martial law in Poland, Wałęsa was interned in Chylice, Otwock Wielki and Abramowo. These weren't conventional prisons, as the authorities tried to convince him to create a fully controlled neo-Solidarity at that time. It didn't work out, Wałęsa didn't commit such a spectacular political suicide, Solidarity remained officially outlawed until 1986, but Wałęsa himself got released in November 1982. There were still some opposition figures and numerous regular activists who ended up again in prison afterwards (Bogdan Borusewicz, Bogdan Lis, Zbigniew Bujak, Adam Michnik, all released by amnesty in September 1986) or were in hiding (Kornel Morawiecki, Andrzej Kołodziej). Perhaps you confused Wałęsa with one of them. This is not such a trivial historical point. Imprisoning a Peace Nobel Prize winner was not something that the half-corroded regime, with little popular support and with dramatic need for foreign loans and investments, could afford at that stage. Ordinary people were often risking more: if you were caught transporting opposition materials, for example, even if you didn't end up in prison, you risked at least your car being confiscated. You can't imagine how many years it took to get a car at that time, if you were ever so lucky. And no BBC or Radio Free Europe would protest on the behalf of some unknown dude or gal. It would have been easier for security services to beat up or sometimes even kill somebody without a high profile, not to mention "trivia" like losing your job. Anyway, regardless of any infelicities, thanks for this interesting recollection! t.

The first experience of Soviet life (in winter) was to discover that the communal hot water did not work as pipes from the power station had burst (actually no one said what happened or even would admit that the system had broken). I recall Helena -- the realist -- making arrangements so that participants could have a bath in another quarter of the city.

At the end of the meeting I still had a huge amount of zloti so Marek took me shopping. This was an interesting experience as it consisted of joining queues to find out what they were queuing for! Needless to say I could not spend all my zloti so I ended up giving them to Marek. I learned that university staff were not really paid a living wage so these perks (and visiting positions in the US -- often brokered by Helena) were essential.

I was always delighted to see Marek at (Category Theory) conferences and will greatly miss him.

-robin (Robin Cockett)

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Obituaries of colleagues are always sad, but they become shocking when they are for friends of exactly one's own age. Marek was a friend, not really a collaborator, of mine. I first met him at the Cambridge CT conference in 1986, when we were each finishing our PhD theses. He helped organise three of my four visits to Poland and was an excellent host to me and my partner. On one visit he helped to return my spectacles to me in London, after I had dropped them in a town in the far NE of the country! My first visit was in 1993, not long after the fall of Communism. Warsaw had been flattened by the Nazis and was now dominated by the Palace of Culture and Science, a "gift" from Joseph Stalin. It was said that the best thing about being in it was that then you could no longer see the Palace of Culture. By my second visit, in 2013, numerous "capitalist" skyscrapers had sprouted up in central Warsaw, so I asked Marek what he thought of them. He replied, "which do you prefer, Typhoid, or Cholera?" It is that dry sense of humour that I will always remember. After the elections in November I asked him what he thought and he gave a typically cynical response. I was hoping to get a more detailed opinion once Donald Tusk had finally got his feet under the prime minister's desk. Now I will not hear what Marek thought. I know his family has deep roots in Warsaw and his uncle died in the Uprising against the Nazis (watched by the Red Army from across the river). Poland is now restoring Democracy for the fourth time. I am very sorry that my friend Marek will not get to see that flourish. My commiserations to his partner Justyna, his two sons, his family and his colleagues. Sorry for he late reply: I was on holiday in S America. Paul Taylor. ---------- You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. Leave group: https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.ashx?source=EscalatedMessage&action=leave&GuestId=6bf90c14-94d1-45b7-a0b5-9dd447734d27