It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues. While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along. Richard Blute, Simon Henry, Philip Scott (University of Ottawa) [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
I am very sad about Pieter's passing. I did my undergrad at the University of Ottawa, where Pieter was one of my teachers and mentors. I did my first research project with Pieter and Pieter was the one who taught me category theory. Over the years, I got to hangout with Pieter at numerous conferences and seminars. I got to work with Pieter and also become friends with him. I always enjoyed having a chat with Pieter and going for food and drinks. Pieter will be greatly missed. My condolences to his family and friends. JS PL On Wed, 4 May 2022 at 04:46, Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
Dear Philip, I am saddened and surprised to learn that Pieter Hoftras passed away. It is unfair, he was still young! He was a warm person and a talented mathematician! His work combines geometric thinking with formal logic. It is a great loss for the community of category theorists. It was always a great pleasure to discuss with him. My sincerere condolences to his family and friends. Best regards, André On Wed, 4 May 2022 at 04:46, Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
I am deeply saddened by Pieter's passing. Pieter was one of my PhD advisors (along with Philip Scott) at the University of Ottawa from 2015-2020. I was also a TA for some of his classes on a few occasions. He was always very kind, respectful, and generous with his time and energy, and he was an insightful and encouraging teacher, mentor, and advisor. He had an immense impact on my development both as a mathematician and as a person. He will be deeply missed. I also send my condolences to his family, friends, and colleagues. -Jason Parker On Tue, May 3, 2022 at 2:46 PM Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
What an awful piece of news. During his PhD, Pieter visited Genova while I was there and he shared a flat above mine in the old town. He was not only a good neighbor but he also became a good friend indeed. If I remember correctly, he had a degree in Philosophy. His conversation was kind, clever and entertaining. We did not always agree on academic matters but I always tried to meet with him during the ct's to talk and recall our days in Italy under Pino's protection. Last time was at the Bow Bar in Edinburgh where we talked about his work with Jon and about how much he enjoyed being a father. M.
---------- Forwarded message --------- De: Philip Scott <scpsg@uottawa.ca> Date: mar., 3 de mayo de 2022 2:46 p. m. Subject: categories: Pieter Hofstra To: categories@mta.ca <categories@mta.ca> Cc: Philip Scott <philip.scott@uottawa.ca>
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
I've been thinking about Pieter all day. He spent some months with us at Carnegie Mellon visiting Steve Awodey during the early stages of my PhD. During that time he taught me a lot, and also gave me some sage advice at a time when I needed it. I will miss the kind and generous way that he would explain things, and I am shaken that I will never get to talk with him again. My condolences to his family and close friends, and to the category theory community as a whole. This is a great loss. Sincerely, Jon
On May 3, 2022, at 8:32 PM, Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
This is very sad news indeed. Pieter was a postdoc with me at Calgary 2005/6 before he moved (back) to Ottawa as a member of faculty. While in Calgary he developed with me the theory of Turing categories (abstract computability). Subsequently, we kept in touch and he was a frequent visitor at our home: I valued him not only as a colleague but also as a friend. Pieter was very popular amongst the mathematicians at Calgary as he gave incredibly clear well-organized seminars on a wide variety of topics. He was also, for the same reason, a very popular teacher. While at Calgary, Pieter supplemented his meager postdoc salary in a rather unusual way. He would play poker on-line. He was incredibly disciplined about it ... and invariably walked away with a profit. To him it all seemed very simple! When he moved to Ottawa he started a course in gaming which I understand was very popular (although I rather doubt whether his students could bring the same discipline to it as Pieter). I will miss him. -robin (Robin Cockett) ________________________________ From: Philip Scott <scpsg@uottawa.ca> Sent: Tuesday, May 3, 2022 12:32 PM To: categories@mta.ca <categories@mta.ca> Cc: Philip Scott <philip.scott@uottawa.ca> Subject: categories: Pieter Hofstra It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues. While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along. Richard Blute, Simon Henry, Philip Scott (University of Ottawa) [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
I am devastated by the death of my dear friend and colleague Pieter Hofstra. Pieter was one of my closest friends in the world. It is one of the extraordinary things about being a mathematician, that one becomes close friends with people even without ever having lived in the same place as them. I met Pieter at the PSSL in Braunschweig in April 2000 when we were both PhD students. It's particularly crucial to make friends at conferences when you're a PhD student and new to everything, because it's all so daunting. I rely heavily on surrounding myself with friends. Pieter was one of the friends whom I relied on at conferences and also in all of life. We became friends immediately, connecting over category theory, Schubert, espresso, single malt whisky. Pieter was the best friend I can imagine. He was always there for me through the amazing ups and terrible downs of these last 22 years. He had the sharpest perception, wriest wit, and the most exquisite command of the English language despite it not being his first language. He helped me understand category theory that I felt stupid for not understanding, but he never made me feel stupid. He gave beautiful talks, and taught me the amazing technique of planning board talks actually board by board to ensure a good layout of notes on the boards. As Robin mentioned, Pieter was an accomplished poker player and gave an extremely popular maths course on the maths of poker. At the end of conferences we had a tradition of going to a casino and spending the evening at a poker table. We would both put money in, and then I'd watch as he calmly doubled or tripled it. I know nothing about poker, but I enjoyed watching the other players trying, and failing, to size him up. At the Kananaskis workshop in 2006 we were halfway through a bottle of Islay whisky when he offered me some more and said "More whisky, Dear Colleague?" and for some reason we took to addressing each other as Dear Colleague for ever more. It was a ridiculous moniker for someone who was so much more than a colleague, but Pieter was the master of understatement. I miss my Dear Colleague terribly. I am devastated, and my life will never be the same. My heart goes out to all those mourning his loss. Eugenia On Tue, May 3, 2022 at 2:47 PM Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
Dear Friends and Colleagues, I send my condolences to all of Pieter's family, friends, and colleagues. The news of his passing last week deeply affected me. Pieter and I were postdocs around the same time, meeting occasionally at conferences, such as Octoberfest and CTs. I felt a bond with him, being from the same generation, and I think anyone who knew him felt a bond because of his personality. He had such a beaming smile and patient, friendly, kind way of explaining and discussing. The way he discussed mathematics was full of youth. And so was he. I was so shocked and sad to read the news of his passing. I just can't grasp it. Sincerely, Tom Fiore [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
Dear all, I have also written up some memories of Pieter; they can be found at https://webspace.science.uu.nl/~ooste110/hofstramemory.html Best to all, Jaap ________________________________ Van: Eugenia Cheng <echeng4@saic.edu> Verzonden: donderdag 5 mei 2022 18:10 Aan: Philip Scott <scpsg@uottawa.ca>; categories@mta.ca <categories@mta.ca> Onderwerp: categories: Re: Pieter Hofstra [U ontvangt vaak geen e-mail van echeng4@saic.edu. Informatie over waarom dit belangrijk is op https://aka.ms/LearnAboutSenderIdentification.] I am devastated by the death of my dear friend and colleague Pieter Hofstra. Pieter was one of my closest friends in the world. It is one of the extraordinary things about being a mathematician, that one becomes close friends with people even without ever having lived in the same place as them. I met Pieter at the PSSL in Braunschweig in April 2000 when we were both PhD students. It's particularly crucial to make friends at conferences when you're a PhD student and new to everything, because it's all so daunting. I rely heavily on surrounding myself with friends. Pieter was one of the friends whom I relied on at conferences and also in all of life. We became friends immediately, connecting over category theory, Schubert, espresso, single malt whisky. Pieter was the best friend I can imagine. He was always there for me through the amazing ups and terrible downs of these last 22 years. He had the sharpest perception, wriest wit, and the most exquisite command of the English language despite it not being his first language. He helped me understand category theory that I felt stupid for not understanding, but he never made me feel stupid. He gave beautiful talks, and taught me the amazing technique of planning board talks actually board by board to ensure a good layout of notes on the boards. As Robin mentioned, Pieter was an accomplished poker player and gave an extremely popular maths course on the maths of poker. At the end of conferences we had a tradition of going to a casino and spending the evening at a poker table. We would both put money in, and then I'd watch as he calmly doubled or tripled it. I know nothing about poker, but I enjoyed watching the other players trying, and failing, to size him up. At the Kananaskis workshop in 2006 we were halfway through a bottle of Islay whisky when he offered me some more and said "More whisky, Dear Colleague?" and for some reason we took to addressing each other as Dear Colleague for ever more. It was a ridiculous moniker for someone who was so much more than a colleague, but Pieter was the master of understatement. I miss my Dear Colleague terribly. I am devastated, and my life will never be the same. My heart goes out to all those mourning his loss. Eugenia On Tue, May 3, 2022 at 2:47 PM Philip Scott <scpsg@uottawa.ca> wrote:
It is with great sadness that we announce that our dear friend and colleague Pieter Hofstra (1975-2022) passed away unexpectedly on May 1. Pieter obtained his PhD from Utrecht University, under Jaap van Oosten, studying realizability toposes. His research interests included general topos theory, realizability, inverse semigroups and groupoids, abstract computability, and homotopy type theory. Among his recent works, with J. Funk he introduced the notion of isotropy groups of toposes, which he was actively developing with students and colleagues.
While Pieter was a brilliant researcher, a kind teacher and a caring supervisor, we will most remember him as a friend. When we have any details for a memorial service, we will pass them along.
Richard Blute, Simon Henry, Philip Scott (University of Ottawa)
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
participants (10)
-
Eugenia Cheng -
Jason Parker -
Jon Sterling -
Joyal, André -
JS PL -
Matias M -
Oosten, J. van (Jaap) -
Philip Scott -
Robin Cockett -
Thomas Fiore