# Mathematics & Statistics Department

## In Remembrance of Hugh Chrestenson (1927-2021)

Here is a treasured photo I took of Hugh Chrestenson in 1986. Behind him are Joe Roberts and Ray Mayer, the event was the annual math dept picnic, which was at Rao Potluri's house in those days. Since then the math dept has outgrown anybody's backyard for the spring picnic. I believe that Hugh was the master grill cook for all the picnics back then.

Hugh was my first teacher at Reed, Fall 1983, MATH 200, 8am MTWF. On the way to his office around 6am he'd stop by the classroom to open the windows, for fresh and cool/cold air. Hugh was a master teacher, he assigned great homework, gave us crucial constructive and prompt feedback, he supplemented the textbook with best possible examples and presentations, and he kept our attention with just a little additional help of opening more windows, so that we would not get too comfortable.

A distracted student questioned him once in class why df/dx isn't abbreviated to f/x, and Hugh's memorable answer was that that would be like abbreviating REED/COLLEGE to RD/COLLG (he was cancelling the Es with definite strokes in the denominator and the numerator).

One of the exercises in that class was to prove that the field of complex numbers is not ordered. I was a novice at proof writing and needed help. Mark Galassi and I were showing Hugh a step in our reasoning, prompting Hugh to exclaim in his humorous shocked voice that we cannot assume that -1 is smaller than 0. David Griffiths happened to be walking by and promptly told Mark and me to come instead to the physics department where they do know that -1 is smaller than 0.

I remember several aha moments from his class, when things just fell together nicely and I could see the next glimpse of the universe. The biggest glimpses were of how we reason and write proofs. At first I didn't understand why I would need to prove Leibniz's product rule formula for the n-fold derivative or that saying that something is false is most convincing by constructing a counterexample. (I still remember 30 points off an exam with 100 points total for not giving a counterexample, it stung convincingly and taught me a permanent lesson!) But by the end of the semester I was becoming a decent proof writer, and I still do that (and keep getting better). My teaching and my prompt grading has definitely been influenced by Hugh.

In my senior year he was my thesis advisor, and gave me the confidence that I needed at that time. At departmental parties he and Doris modeled a harmonious relationship I'd never seen before. At departmental events, when it was not all that late yet, he'd announce to Doris: "Mama, it is time to go home." I liked how they talked to each other (and I also liked their regular early-to-bed-early-to-rise sleep schedule.)

At the time when Reedies were more on the "free love" side and when another professor spent precious class time expounding on how two mathematicians (mathematics students) should not get married because it just won't work, Hugh instead was very supportive of Steve and me getting married, as we did at the end of my junior year (Steve had graduated). As a wedding gift Hugh gave us a wooden fruit bowl that he turned himself; we still have it, use it, and treasure it. Steve and I have many wonderful memories of visiting Hugh and Doris in Forest Grove and of their visit to us in New Mexico. On one trip to their almost-finished house in Forest Grove, we helped with putting the roof on with a few other people. At some point, Hugh fell through the roof frame but caught himself by his elbows. The rest of us froze in inaction, but after a moment Hugh said, in his characteristic cool fashion: "Hm, I think I'll need a ladder under my feet."

There are many other wonderful memories. Of teaching our son how to use the lathe. Of gifting us more lathe-worthy wood. Of getting together with us, sharing stories about their children, Doris showing her quilting, Hugh sharing his home-made beer, showing us their amazing house that they designed and built in Forest Grove

Irena Swanson ’87