Bill Lawvere 1937--2023

Bill Lawvere 1937--2023

[ptj]

I am devastated by the news that Bill Lawvere passed away yesterday.
Truly, we have lost one of the giants of our subject. I imagine
everyone on this list will have their own special memories of him;
here are a few of mine.

It was fifty years ago this month that I first corresponded with Bill,
sending him the first draft of my paper `The associated sheaf functor
in an elementary topos' (which he accepted for publication in JPAA).
I still have the reply he sent me: re-reading it brought tears to my
eyes as I remembered the very considerable trouble he had taken to
help and encourage a young author who was then totally unknown to him,
by giving me excellent advice on how to sharpen the presentation of
the paper.

We met a few months later, at the Aarhus Open House in May 1973; it
was there that I aroused Bill's anger by presuming to give a talk about
John Conway's theory of numbers and games, which Bill thought (wrongly)
to be antithetical to his very strong political views. But the storm
passed, and Bill remained a staunch supporter of my work (though I could
always rely on him for frank criticism of any imperfections in it).

When, in September 2004, Jiri Adamek suggested to a group of
senior category-theorists that there was a need for a `steering
committee' to ensure the continued smooth running of international CT
conferences, there was lengthy discussion about almost every aspect of
his proposal; but one thing which nobody queried was his suggestion that
Bill should be invited to chair the committee. Happily, Bill accepted
the invitation (on condition that I should agree to be the secretary),
and he provided us with wise and thoughtful guidance until he stepped
down in 2010.

The organizers of the 2007 CT meeting in Carvoeiro decided to make the
celebration of Bill's 70th birthday a theme of the conference, and they
invited me to give a laudatory talk summarizing Bill's mathematical
achievements. It was an invitation I accepted with considerable
trepidation, and even 24 hours before the talk was due I was unsure
how I was going to do justice to all aspects of Bill's work. But in the
event it went well, and Bill approved of it; he was particularly amused
that I'd included a quote from Karl Marx on one of my slides (he
thought, incorrectly, that I hadn't been aware of its source).

But there's no need for me to recall anything I said in that talk;
Bill himself did the job of summarizing his work much better, in an
interview with the Coimbra mathematicians which is available online.
Reading it again today, I'm struck once more by the extraordinary
mathematical mind of a man I've been privileged to know for almost fifty
years. RIP Bill; we'll all miss you.

Peter Johnstone





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