In memory of Kalevi Suominen
Oscar Benjamin
It is with great sadness that I bring the news that Kalevi Suominen
(@jksuom on GitHub) passed away on the 4th of March. Kalevi's son
Risto passed on this news to me and some others by email yesterday.
I never met Kalevi in person but we had many conversations online over
many years. Kalevi was an outstanding SymPy contributor and was
involved with the project long before me and so there are others here
who have known him much longer than I have. Kalevi guided many SymPy
contributors and supervised many GSOC students over many years.
Looking in the git history his earliest commit was from almost exactly
10 years ago.
Personally I learnt a huge amount from Kalevi and I am very grateful
for the time he took to teach me and others and to guide the project
generally. Kalevi's expertise in many areas of Mathematics and across
the full depth of many parts of the SymPy codebase was unmatched
within the community.
Interacting through GitHub I guess that many of us did not realise
that Kalevi's health was in decline. He continued to be involved
including most recently reviewing a pull request just 6 weeks ago. A
few weeks ago he sent me some files with what he was most recently
working on but was no longer able to finish. I will try to complete
that work and submit it as Kalevi's final pull request.
Kalevi's passing is a huge loss to SymPy but I don't want to dwell on
that. Instead I invite those of us who have known Kalevi to share
their thoughts and memories here.
Oscar
Jason Moore
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Oscar Benjamin
I checked with Kalevi's son just to be sure and yes, that is the same Kalevi.
He completed his PhD in 1966:
https://www.genealogy.math.ndsu.nodak.edu/id.php?id=20539&fChrono=1
Then after a long career teaching Mathematics at the University of
Helsinki he got involved with SymPy development as a retired Maths
professor. Given his breadth of knowledge I had always assumed that
his background was something like this although I never thought to go
and look it up.
Oscar
Aaron Meurer
I had the honor of meeting Kalevi face to face once on a video call
many years ago, but other than that, like everyone else, I primarily
interacted with him online. Kalevi was always known in the SymPy
community as the mathematics expert. As a retired professor of
mathematics, his knowledge greatly assisted the development of some of
the deep mathematical areas in SymPy, such as the polynomials and
group theory modules. He was always available to give advice whenever
I was unsure of some part of SymPy that was outside of my domain of
expertise. I was always impressed by the breadth of his mathematical
knowledge, as well as his skill as a Python programmer, a combination
which can be rare to see.
Yet despite being easily the most mathematically adept member of the
community, he never lorded it over us, but always approached every
interaction with kindness and humility. He considered himself to be an
equal and as both a teacher and a learner. He can be a model for the
sort of contributor and community member we should all strive to be,
and our project was truly lucky to have him.
I found some of the papers and books he wrote on Google Scholar
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C32&q=Kalevi+Suominen&oq=
and MathSciNet (but this requires a subscription to view, which I do
not have) https://mathscinet.ams.org/mathscinet/MRAuthorID/209375. He
never mentioned this work, and it seems like most of it deals with
technical mathematical areas which are not directly relevant to SymPy.
I'll close on the following paragraphs from Kalevi himself, which I
found in an old private email from 2018, on why he contributed to
SymPy:
> Being retired, I consider myself lucky as I can work with open code
> on my own time with no pressure. It seems that many pensioners find
> themselves a hobby. This is what suits me.
>
> I originally came across SymPy when searching for a mathematical
> library for experimenting with some algorithms. It was (almost)
> "love at first sight". It does not matter that the language, Python,
> is not the most efficient one. It is easy to work with, and very much
> readable. Readability is important to me as it helps in finding
> errors. (That is what I had been doing for a great part of my
> professional life.) It was also of importance to me that functions
> would look familiar, sin(x), not Sin[x]. Instead of simply using
> SymPy I finally found myself wanting to improve the library,
> but that is another story.
Aaron Meurer
Peter Stahlecker
Peter Stahlecker
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Ankit Kumar Singh
Ankit
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Amit Kumar
Abhinav Anand
Francesco Bonazzi
Anderson Bhat
This is very sad to hear for me. Being someone who worked with him for like 6 - 8 months (Oct 2021 - Apr 2022 while I used to contribute to the Series & Limits module and May 2022 - Aug 2022 while Kalevi was my GSoC Mentor) , I can say that this is a huge loss for the community. If you see my PRs from Oct 2021 to Apr 2022, almost all have been merged by Kalevi cause we were trying to solve some fundamental issues in the series module and the code for that was written back in 2008 - 2010, so it needed some special attention and refactoring. I always felt that his reviews on my PR were so spot on.
This also led to my GSoC project where we tried addressing more relevant issues. I was in touch with him over chat for about 3 months on a daily basis, though sadly I never met him over video. I remember we used to brainstorm on approaches to solve an issue and as usual he had and approach and I had a counter approach which I felt would work out too. So I used to challenge him and he always gave me the freedom to try (and I think he knew I would fail) and then get back to his approach. Specially on this PR ( https://github.com/sympy/sympy/pull/23592) . This happened a couple of times after which I knew that whatever he says is backed by his experience as a SymPy developer and I shouldn't be challenging him.
Hence being someone who got a chance to work with him closely, I can say this is huge loss for the sympy community. I know a couple PRs where Kalevi had an approach in mind and had mentioned it but nobody tried addressing it, for eg https://github.com/sympy/sympy/pull/25756#issuecomment-1864176011 . I shall try looking into this whenever I have time.
Regards,
Anutosh Bhat
Gaurav Dhingra
Kaj Malm
Dear Oscar Benjamin,
I hope this mail will find you although I do not know your personal address.
I was the first doctoral student and later a colleague of Kalevi Suominen at the University of Helsinki, so it goes without saying that I share your sadness and all the positive thoughts about him I find on the SymPy pages.
Kalevi became a member of the Finnish Academy of Science and Letters at the tender age of 33 years, and therefore the Academy will publish an obituary in due time, both in Finnish and in English. Most likely we have to wait for that until next year, and meanwhile I would like to write a less technical version to be published by the leading Finnish newspaper, possibly together with other students and colleagues of Kalevi. The problem is that I left the University of Helsinki decades ago, and thus I do not know how to get in touch with his children (his wife Pirkko passed away just a few months before he did). Legally speaking an obituary can be published without the consent of the family, but I find it polite to inform the family and I would also like to check some facts about Kalevi.
In conclusion I'll ask you for a favor: could you be kind enough to send me the email address of Risto Suominen (by pm)?
Yours sincerely
Kaj Malm
bkmmalm(at)gmail.com
Oscar
Oscar
https://www.hs.fi/muistot/art-2000010543947.html
Mathematics as a part of life
Professor Kalevi Suominen passed away in Helsinki on March 4, 2024, according to his wish at home. He was 83 years old, born in Helsinki on July 20, 1940.
Suominen matriculated at the Finnish co-educational high school of Pori in 1958 and then began studying at the University of Helsinki. During the first academic year, his fellow students could already read on the notice board of the mathematics department that he had completed the legendary difficult "big integral", i.e. the final phase of mathematics studies, with a grade of 3/3.
In 1967, Suominen completed his doctoral dissertation on the theory of quasiconformal mappings, which at the time was the most important focus area of Finnish mathematical research. Three years later, he was appointed associate professor of mathematics at the University of Helsinki. The post was later changed to a full professorship.
Suominen did not only study quasiconformal mappings, but wrote publications in many fields. He was able to supervise dissertations in the fields of algebraic geometry, algebraic topology, category theory and number theory.
As an editor of Mathematica Scandinavica, he supported the authors with his sharp observations. In his seminars, he discussed, for example, the latest results of the French Bourbakists. He also occasionally worked as a visiting professor or researcher, e.g. in Denmark and Sweden.
Suominen was rewarded for his merits in many ways. He was elected a member of the Finnish Academy of Science and Letters at an unusually young age in 1973.
Mathematics was an important part of Kalevi's life until the end. In retirement, he participated in international conferences, and as a new hobby he had the development of an open source library for symbolic computing together with young enthusiasts. According to his partners, he was one of the leading mathematicians of this SymPy project. They admired his uncomplicated, egalitarian attitude towards his juniors.
His students and colleagues at the university had the same experience: Kalevi was modest and friendly. He invited his graduate students to his home for visits and also participated in their family events. In coffee table debates, Kalevi could surprise you with his knowledge of the most diverse fields. However, he never tried to knock out his interlocutors verbally, but in his gentle way contributed to their general education.
The fact that he passed away just a couple of months after his beloved wife Pirkko speaks of the strength of Kalevi's family ties. His loved ones also included the children Laura, Risto, Liisa and Markku and their families.
Kaj Malm
Student and colleague of Kalevi Suominen.