Saying good bye to Harold

 Harold wasn't ill, as far as I know. He seemed to be enjoying his life as an avant-guarde musician, and was due to perform two days (or something like it) after he died. I read it in the website of the venue when I tried to learn more. This seems so unfair! 

Harold A. J. M. Schellinx was very, very clever and a good person. He helped me a lot when we were both starting. I finished my doctorate earlier than him, because he did so much for his. I am still trying to learn some of the things he wrote in 1994! Last time I wrote to him, around 2005, I was trying to get him to publish his thesis in Lulu. Amazon said it had one copy for more than 200 dollars and I said it would be nice if he did republish it. He replied that he still had plenty of copies and if I knew someone who wanted it, I should give them his email. Fair enough.

Harold could have destroyed my career, if he wanted to. He found a big hole in my work and helped me to try to fill it. Which I did, many years later. Andreja Prijatelj was a common friend, who departed  earlier in 2002.

I started this post in September, when I heard the bad news from Jean-Baptiste, via Luiz Carlos. It hurt. Much more than when I heard about Thomas Streicher. At least I had had a chance to catch up with Thomas in Padova, to have lunch and chat about the world with him. I don't think he knew already about his disease. I didn't, for sure, and thought it was only a lovely chat after so many years apart. And that this would become more part of my life now that I only work on things I want to. Little did I know that this was the last time I would see him alive.

But Christmas is the season for ghost stories and for self-recrimination. And  I do have these in spades. I don't mean in epic proportions, like Dicken's `The Christmas Carol' Scrooge, but it feels really heavy right now. I guess it happens to everyone,  reason why the holidays can be so fun and at the same time so sad, so difficult to survive! All that I need to do is be less self-centered, think more of others, understand better what matters to them and act on it. It shouldn't be so hard. (One thing I like about myself is the very Brazilian habit of always thinking we can do it, that there is always new chances and new beginnings).

Ada Lovelace Day 2025

 

 

 Phew! I almost completely missed it! This year's Ada Lovelace heroes are Larisa Maksimova and Ewa Orlowska. Someone once said (and I repeated it dozens of times in talks and in writing) that starting a project is easy; difficult is keeping it up, year after year.  Maintenance is much harder than starting new things. It's not sexy, I can be very boring. I seem to be falling prey to this difficulty now. I have been doing Ada Lovelace Day posts since 2011. Nowadays it should be easier, since I can decide what I want to be working on. But instead it is turning harder: focusing on projects and finishing them off turns out harder if you make your own deadlines.

Anyways, as usual, better late than never. This year, I went back to basics and chose two mathematical logicians, as it was the original goal.  When I was growing up, I had the impression that many logicians, especially from the Iron Curtain countries, were women. They seemed established professionals; they looked much older than the corresponding authors from the West. They also morphed into a jumbled mass in my head. Now I realize the huge differences in subjects, approaches, cultures, etc.  Now I feel that I should try to learn the history of logic/mathematics and its nuances, checking out all the manipulations of  the winners, who write the (lack of) history. (Yes, we have a project on history of Mathematics in the BRICS countries, I have much to learn from my historian friends.) Anyways, here goes the two heroes of 2025:

 Larisa Lvovna Maksimova (5 November 1943 – 4 April 2025) was a Russian mathematical logician known for her research in non-classical logic. Sergei Odintsov (kudos to him!) edited  Larisa Maksimova on Implication, Interpolation, and Definability, Outstanding Contributions to Logic, vol. 15,  2018, a festschrift for her. I just bought the book and I hope to learn what she was doing with strict implication!

But to end on a positive note, the second hero is Stella Ewa Orłowska (born 1935),  a Polish logician. Her research centers on the concept that everything in logic and set theory can be expressed in terms of relations, and has used this idea to publish works on deduction systems and model theory for non-classical logic, and logics of non-deterministic and incomplete information. 

Professor  Orłowska has many  books under her name. She also has a festschrift book, pictured below. Just as well, as I could not find a picture of her today. But I do remember seeing several pictures in previous years. According to Google Scholar  professor Orłowska has a 2025 arxiv paper, joint work with Viktor Marek and Ivo Düntsch on Rough Sets. Wonderful to hear!