In Memoriam: John (Jack) Wetzel

Jack Wetzel

John (Jack) Edwin Wetzel, University of Illinois Mathematics Professor Emeritus, died on November 29, 2021. There will be no services.

Born in Hammond, Indiana on March 6, 1932, Wetzel was the son of Miles Thomas Wetzel, an electrical engineer, and Isabel (Bella) Barnhart Wetzel, an elementary school teacher.  He spent his childhood in Goshen, Indiana and graduated from Goshen High School in 1950.  He received a BS from Purdue in 1954 and a mathematics PhD from Stanford in 1964.  He joined the Department of Mathematics at the University of Illinois in 1961 and retired in May 1999.

Obituary (Champaign-Urbana News-Gazette)


In 1999, upon Professor Wetzel's retirement, Professor Bruce Reznick made the following remarks ...

I was delighted when Philippe [Tondeur, then-department chair] asked me to speak on behalf of Jack Wetzel. This gives me the pleasure to talk about the crispness of his mathematics and the warmth and generosity of his personality.

Jack was born and went to school in Goshen, Indiana. One of his classmates was ... well I'll get to that later.

He attended Purdue University and then went to Stanford for his PhD. Mahlon Day hired him to be an instructor in 1961, while he was still working on his thesis. There were 18 math faculty hired that year, including M.-E. Hamstrom.The topic of his dissertation was harmonic functions on Riemann surfaces, and his advisor was Halsey Royden.

Jack's early involvement in the department was mainly on the teaching side. He'd frequently give talks in high schools, and he helped run the Summer Science Training Project for gifted high school students, which was funded by the NSF. When I asked people who were here then what else I should talk about, they spoke as one: "The Beard." Jack's beard was born in 1961, while he was recovering from the flu, and died in 1965, when he was afraid it would scare off the parents of his high-school charges.  It was a long beard. I've seen some snapshots, and,  when combined with his flat-top, it made him look like a 1999 militia leader. A contemporary who asked to remain anonymous has said, "He could have worn a coat and tie without the tie. The grad students all referred to him as Fuzzy Wetzel."  Not that there's anything wrong with being fuzzy.

Jack eventually his research interests from complex analysis to combinatorial geometry -- a fiendishly tricky subject. Jack has written more than 30 papers so far, for such journals as Discrete Mathematics, Geometrica Dedicata, Journal of Geometry, AMS Proceedings and Transactions, Israel Journal, the Monthly and Mathematics Magazine.

One of Jack's striking research accomplishments was his classification of which Grunbaum arrangements are simplicial. This is not the right occasion to explain precisely what this means. His other research has been more easily described, in fact, Paul Bateman once complained to him: "The trouble with you, Wetzel, is that everyone can read your papers!" Jack has been interested in finding convex sets which contain a congruent copy of all sets of a particular kind; for example, all curves of length 1. He and Zoltan Furedi have recently determined the smallest convex set that can accommodate all triangles with perimeter 2. Jack's most widely read paper might be his article on Napoleon's Theorem. Napoleon's Theorem  involves triangles, but not, according to the best historical analysis, Napoleon.

Jack's PhD student Steve Knox wrote his dissertation on the relationship between the number of faces of a convex object and the number of edges in its shadow -- a suitable training for his current job at the NSA. Since Steve couldn't talk about his research, he told me about his working relationship with Jack. Throughout, Jack's advice was always in the form of mild suggestions -- "You might want to look at this paper...," "I've heard this person's name in this area...," etc., with one exception.  He once directed Steve to "buy Robert Byrne's Standard Book of Pool and Billiards and practice its contents." Steve regards the greatest failure of his graduate school days to be that he never developed a good closed bridge.

Let me turn to his teaching. Harry Levy once called him "the best teacher the department has ever seen." His lecturing style is a model: crystal-clear and crisp presentation, rigor matched with the perfect illustrative example. Students loved his Math 440 courses, and one year, a class of 35 to 40 -- that's a graduate class! -- gave him a spontaneous ovation at the end of the semester. In the mid-70s, a graduate student came into Jim Armstrong's office and  quite forcefully demanded to know what course Prof. Wetzel would be teaching the coming semester. He said that he didn't care which course it was, just to sign him up! Another colleague reports on receiving the following advice on a teacher evaluation form --- "To be a good teacher, be in all ways like Prof. Wetzel." Among many other things, I learned an indispensable term from Jack:  a mistake made at the blackboard is to be called a "chalkographic error".

I first got to know Jack well through the Geometric Potpourri seminar, which he has organized for the last several years, taking over after Ralph Alexander's retirement. The Geometric Potpourri is a marvelous long-running conversation on all things geometric, construed broadly, and it's has been one of the most enjoyable parts of my academic life. Jack has tirelessly organized the Geometer's Lunch, which meets in the Ballroom on Tuesdays, and dinners when we have out of town speakers, making sure they are at good restaurants, at least by Urbana standards.

For the last few years, a colorful group of people has regularly shown up in Urbana to talk about the classical study of triangles at the Geometric Potpourri.  These include a retired professor of ophthalmology, several mathematicians from smaller schools, and a Pulitzer Prize-winning computer scientists.

Why triangles? Clark Kimberling of the University of Evansville quotes Jack in the introduction to his recent book on the subject -- "This subject has more miracles per square meter than any other area of mathematics."  At the March AMS Meeting in Urbana, Jack and Clark organized a special session on "Recent Progress in Elementary Geometry". There were 18 speakers -- from as far away as Canada and Wales and Germany. And  four speakers listed no departmental affiliation, showing how much of an outreach this is to the larger community of the mathematically interested.

As Clark wrote me: "This was a marvelous experience for these speakers, not only to share geometric ideas, but to stay in touch with a major center of mathematical activity."


Jack and Becky are inseparable. They've been married since 1962, but first met in elementary school. Nothing else needs to be said.


To sum up, I'd like to quote from Douglas Hofstadter, the computer scientist and unashamed geometry-lover, on Jack Wetzel:

"He is humanly warm, he has a nose for what is beautiful in mathematics, he perks up at every beautiful result that someone presents, he asks elegant questions that suggest new ideas, and he has a terrific sense of humor.  He is great company and someone who really knows what makes mathematics fun, and knows how to convey that to others as well."

Jack Wetzel has made our Department a better place during his time here and I speak for all when I thank him and look forward to more of the same in the years to come.