Two Days

Two Days

[Colin McLarty]

	Working on the history of category theory I find that Mahlon Marsh Day
hired several category theorists at the University of Illinois
Champaign-Urbana in the 1960s. I would like to know whatever people can
tell me about his connections to category theory--perhaps through Eilenberg?

	Also, does anyone here know whether Mahlon Michael Day was Mahlon Marsh
Day's son? Mahlon Michael Day got a PhD at Chicago in 1967 with Kaplansky.

Thanks, Colin

Re: Two Days

[Michael Barr]

I knew Mahlon Day at Urbana quite well.  If he had a mathematician son, I
was unaware of it, but you should ask John Gray.  Now as far as I know he
didn't hire so many category theorists.  For example, I was hired by Paul
Bateman.  So was Jon Beck.  As far as I can tell, the only one hired by
Mahlon was John Gray.  And he may have known Eilenberg, but only as one
mathematician may know another.  But your entire question is based on a
misconception that the hiring at Illinois was based on any sort of plan.
The fact is that there was a severe shortage of mathematicians in those
days and UI was hiring a couple dozen people a year (and losing a similar
number) and anyone who was publishing or well recommended and showed any
interest was getting offers.  I got at least one utterly unsolicited firm
offer from a school I had had no contact with.  Possibly, probably,
someone like Sammy had given them my name when asked, but that is all.
And I received a number of invitations to apply for a job and did and got
an offer (and a pay raise from UI).  So they didn't even ask what kind of
math you did, only that you did some kind of math.  Hard to believe what
it was like in those days.

The people at Illinois who were there for the first midwest category
meeting in 1965 were Alex Heller (an algebraic topologist, with an
interest in category theory), John Gray (category theorist), Jon Beck
(algebraic topology & category theory), Max Kelly (there on a one year
leave, category theory), and me (homological algebra).  In fact, I wasn't
even invited originally; I can thank Max for telling Saunders to invite
me.  My interest in category theory developed later at the ETH.  Now
Eckmann is probably the one person most responsible for bringing category
theorists together.  

A history of category theory should talk not only about the founding
fathers, but also a certain number of godfathers, people who were not
category theorists themselves, but strongly encouraged it.  I would
include (but not limit it to) Beno Eckmann, Peter Hilton, Alex Heller,
David Harrison, ....  Of course, there were a number of others who while
not primarily category theorists made actual contributions to category
theory: Grothendieck, Dan Kan, Albrecht Dold and Dieter Puppe,...

Above all, Colin, one should not write a history of category theory
without interviewing as many of these people as are still alive and it is
damned shame that no one has done this till now.  For Eilenberg and
Harrison, it is already too late.

Michael


On Thu, 6 Dec 2001, Colin McLarty wrote:

> 	Working on the history of category theory I find that Mahlon Marsh Day
> hired several category theorists at the University of Illinois
> Champaign-Urbana in the 1960s. I would like to know whatever people can
> tell me about his connections to category theory--perhaps through Eilenberg?
> 
> 	Also, does anyone here know whether Mahlon Michael Day was Mahlon Marsh
> Day's son? Mahlon Michael Day got a PhD at Chicago in 1967 with Kaplansky.
> 
> Thanks, Colin
> 
> 
> 
>