Re: Pieter Hofstra

[Robin Cockett <robin@ucalgary.ca>]

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

[△EXTERNAL]



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)


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