I took over as director of Cornell's Center for Applied Mathematics (CAM) on July 1, 2020. With a lot going on at Cornell and in the world, I got into the habit of sending out regular emails. Sometimes, I include a sermon at the end of the message. It's an idea that I happily borrowed from Prof Sandy Mack, who ran the Honors Program at UMD when I was an undergrad, and also sent out such sermons.


Faculty sometimes get reminders that natural or political catastrophe are affecting some group of students, and maybe school work and deadlines are justifiably less important to them at the moment than the safety and well-being of their home and family. Given that you are all spending at least a part of your life here, insurrectionists storming the US Capitol with the encouragement of sitting politicians is the type of political catastrophe that could reasonably rattle any of us. It has certainly rattled me — enough that it’s hard to keep track of other stuff.

In normal times, I think any one of the elections in Georgia, or the no-charge decision in Kenosha, or the continuing drumbeat of bad news about COVID and the economy would be the dominant story of the first full week of a new year. Or maybe we would still be getting filler pieces about the psychology of sticking to New Year’s resolutions, or analyses of the first days of the post-Brexit UK. But while 2020 is over, we are still not in normal times.

For the most part, academics get the privilege of thinking long-term thoughts — certainly much more so than many of our peers in business. That doesn’t mean we’re immune to short-term chaos. If you’re having trouble focusing, be gentle with yourself. And, if you are able, turn off the news, take a walk, talk to a friend, do the laundry, and remind yourself of the everyday.

I’m looking forward to seeing you all when classes start back up in February. I hope to return to radio silence until late January, but of course will send a note if things come up (hopefully related to Cornell logistics). But I’m back at it myself, and you know where to find me if you need anything.


Well, you’ve survived the rolling ball of disaster that was the Fall 2020 semester. It was deeply weird, upsetting, and unsettling, for me and for many of you. It was not what I thought I was signing up for when I agreed to the role as director — and probably not what any of you thought you were signing up for when you decided to come here for graduate school!

And yet: amidst the struggle, I saw many of you grow.

I saw you grow technically. Everything takes three times as long as it would in a normal year, but I kept seeing you learn new things — and I learned new things from many of you. We asked you to suggest speakers for the colloquium, and there were some phenomenal choices. I asked you to tell me about your research in late September, and you provided one of the most fascinating afternoons I had this year. And despite the chaos of the year, when I talked to you — for twenty minutes at a time in scheduled meetings, for a few minutes after colloquium, for an A exam or setting up a committee — I mostly just got to enjoy thinking about math.

I also saw you grow as humans. I saw you supporting each other. I saw you caring. I saw you challenging yourselves not only to pick up new technical skills, but also to think about the broader world in new ways.

Universities are funny places. They are old, tradition-soaked, conservative to the point of being hide-bound. We still celebrate our major events by donning medieval robes! And yet, through our students, we are constantly reinvigorated, and our programs ever re-built. As with anywhere else, the room to grow and rebuild is greatest when the world has conspired to tear down the old. Well, here we are, at the end of what may be the most destructive year I’ve ever personally witnessed. And here you are as well, continuing to build.

I am proud of all of you, the work you are doing, and the place you are building.


The tradition of harvest festivals is hardly unique to the US, but we have our own peculiar take on it, even apart from the traditions of turkey and cranberries and pumpkin pie.  As a kid in school, we learned about the myth of “the first Thanksgiving,” and even that version of the story involved the survivors of an awful lot of death and disease.  Reading history as an adult, the whole episode feels even grimmer and sadder.  In the early part of our history as a country, the holiday was celebrated intermittently (e.g. Thomas Jefferson, a deist, declined to declare a Thanksgiving holiday while he was president).  It was Abraham Lincoln who declared Thanksgiving as a regular, official holiday, in the middle of the US civil war; and the current date (the last Thursday of November) was nailed down after a bitter fight between Franklin Roosevelt and his political adversaries among the Republicans in the midst of the Great Depression.

And now, we approach the Thanksgiving day as we reach the end game of a deeply weird and unsettling semester in a year rife with tragedy.  I find it hard not to feel sadness and anxiety about a lot of the current situation.  And yet, I’m grateful: for the fact that all of you are still alive, for the continued success of our local community in managing the epidemic, for the opportunity to continue learning new things every day.  And I’m grateful for a day that I will spend at home with my family without the pressures of lecture prep, meetings, and getting the kids to their classes.

So while I wish you all success in your semi-finals and end-of-semester projects, let me also wish you the vision and courage to try to help fix some of the things that are wrong with the world, and also gratitude for the things that are right.


We pay attention to milestones and big goals, but we get there day by day. So get enough sleep, eat right, try to get out and move around if you can. Be patient with your students, your professors, yourselves. Try to learn something new every day. When something goes wrong, roll with it as best you can, and ask for help if you need it. You know how to do this.


A big, messy, ongoing election; in excess of 100K/day infections — what times we live in.

Even in a normal year, this is around the time of the semester that lots starts coming at everyone.  This year, of course, it’s easy to feel like the world is happening to us, and we’re just trying to keep up.  For good or ill, none of us are where we are without a good bit of luck playing a role.  But don’t underestimate your own agency, either, and keep looking for chances to make the world a little better, whether through your technical work or through a kindness to a student, a friend, a random stranger.  Or, per Robert Louis Stevenson: “Don’t judge each day by the harvest you reap but by the seeds that you plant.”


I have a job where I do things I like to do.  I play with math and computers, sometimes getting others to join in, and then I get to tell students about the stuff that I love.  I think this is great!  For me, the joy of it isn’t in papers or prizes, it’s in the day-to-day figuring out.

There are lots of external milestones in undergraduate life: homework, quizzes, exams, projects.  Most of them are on the time scale of semesters.  Grad school has some milestones as well: finding an advisor and committee, A exam, B exam.  But these milestones are fewer and farther apart.

As graduate students, by and large, you are responsible for structuring your days and figuring out how to keep moving forward.  That’s not always a simple task, even in less turbulent times!  And sometimes there is the temptation to just bull forward with the concrete tasks that the world has set for you: grading homework for your class, running experiments prior to a paper deadline, doing the laundry and feeding the pets.  But while these are all important things (certainly your pets think so!), I hope you all are able to take advantage of the rare privilege of exploring what interests you, I wish for you all the mental space to enjoy going to play with your research.


One of the things I remember from my pedagogy course in grad school is Vygotsky’s idea of the “zone of proximal development” (зона ближайшего развития) — the set of tasks that a learner cannot yet do unaided, but can complete with appropriate guidance, the space between “I already know how to do this” and “this is totally beyond me.”  Part of the idea of the ZPD is that learners need to be challenged by things that are just at the edge of their capabilities — or even just beyond their capabilities without help! — in order to make the best progress.

None of you chose to go through a pandemic.  That’s just bad luck.  But you did choose graduate school.  And even in normal times, as we get into the middle of the semester, it’s easy to think “why did I agree to this?”  Classes are hard; research progress feels slow; it seems like you’re struggling with things that those around you are getting.  The first edges of the gray Ithaca winter don’t help.  But you are not alone in any of this.  You made a choice to go into graduate school, pursue mathematical research, live in the zone of proximal development, and take on these challenges “not because they are easy, but because they are hard.”

And remember that part of the idea of ZPD is that you’re tackling problems where you might still need help, whether from an instructor or a peer or just a reference book.  So talk to your advisors and talk to each other — and don’t worry that your ideas might be half-baked!  The only way to get something to be fully-baked is heat and patience.


Get your flu shot.  Make a plan to vote, if you’re eligible.  Go outside and get some exercise.  Get some sleep.  Celebrate your victories.  Talk to a friend.  You know a lot of the things that you need to do in order to keep yourself and your circle moving forward.  Take some time today to do them.  Yes, that homework, paper deadline, etc is important, but you’ll be able to deal with these things more effectively if you are also able to take the time to take care of yourselves.


The first news I read this morning was about the president’s COVID diagnosis.  This came on the heels of diagnoses for people I care about rather more on Thursday night, and other bad health news for my extended family earlier in the week.  The combination reminded me that, though it’s harder with those I don’t know and those I violently disagree with, I aspire to being able to wish happiness and freedom from suffering to all.  In days of anger and upset, finding compassion takes work - it’s easier to see disagreement than to see common humanity.  But for all that, the effort to move toward compassion still seems worthwhile, at least to me.


No serious charges in the Breona Taylor case, and riots after. DHS seems to be proposing a regulatory measure to make life hard for international students again.  The pandemic continue.  And yet: COVID numbers in Ithaca seem under control.  The weather has been beautiful.  It is a strange world at the moment, but many of you are making the best of it.

All these things are true.  It is not a normal time, and seems unlikely to return to anything like normal for a while.  It is OK to be behind, to be frazzled, to not be on your game.  If you can, though, it is also OK to appreciate a sunny day.


No sermon today, but I did want to say a few words about Paul Steen, who passed away unexpectedly one week ago.

In the first year that I was at Cornell, Paul gave one of the talks for the CAM visit day.  I’d met him briefly before, but I remember that I got to talk to him after his talk to the prospective students, because I thought the stuff he was talking about sounded really cool.  I interacted with him several other times in the first couple years about other CAM things, too.  He helped organize the colloquium one year, gave the visit day colloquium another year, and was always around for the field meetings, picnics, and events.  And I saw him on proposal efforts, and at the SCAN seminar, and on student committees.  We never did any research together, mostly just from timing; we shared a number of interests.

Paul was at the top of his field, and was also very down-to-earth.  I never knew him as anything but kind and cheerful.  He laughed easily.  I looked forward to seeing him.  I found out about Paul’s death at the same time that I was responding to an email from him.  He’d written on Aug 28 (two Fridays ago) to say that he was glad to help out with CAM in whatever way he could, that he was enthusiastic about the idea of a “SciML at Cornell” push, and that there might be some eigenvalue problems that would be interesting to chat about (with paper references!).

I am sad that I’ll never get the chance to explore those ideas with Paul.  I think I would have enjoyed it.  But beyond his body of technical work, I think he lived well, laughed often, and will be remembered fondly by many.  So he leaves a great legacy in many senses, and I suppose that is all any of us can hope for when we go.


Today’s inspiration is again borrowed from Sandy Mack (from http://honcol.blogspot.com/2014/11/former-honors-director-sandy-mack-is.html):

Committed realist or idealistic romantic — showing up alert, sane, and compassionate seems more and more to be at least Woody’s 85%, maybe more.

It’s thrilling — because there is almost always room for change, adjustment, repentance, improvement, ecstasy, magic.  It’s exhausting — because we never seem to outgrow the need to grow, fail, learn, and try again.

And isn’t that just the right note to start this semester?  We’re all making it up as we go along, even more so than normal, and it is both thrilling and exhausting.


This week we saw fires in California, hurricanes hitting Louisiana, COVID deaths passing 180K, and the news of police shooting Jacob Blake in the back.  The drumbeat of bad news is a constant background in 2020, but any given piece of bad news is probably hitting some of us disproportionately hard.  For those of you who are teaching this fall, that might be a student in your section.  Or it might be a friend, or it might even be you.  And the year is not over, and we know that there will be more bad news in store.  Fall will turn to winter soon enough, and for many of us it gets harder to cope as the days get shorter and colder.  This will, for many, be a hard year.

So what are we to do?  I have said it before, but it bears repeating: you are your brother’s keeper.  Lean on those around you, and let them lean on you in turn.  Schedule regular check-ins with your friends now, so that those routines will be in place when trouble hits.  Learn about the formal and informal mental health and counseling resources that Cornell offers.  And while I encourage you to strive, to learn as much as you can, and to good research — also be gentle with yourself, your friends, your students, and your mentors.

This is not a normal year, but we’re all in it together.  Good luck to all of us in the coming week as we set to it.


When I was a kid, I used to watch “The Red Green Show” and then “Red Dwarf” and “Doctor Who” with my dad on Friday nights on our local public television station.  Our reception was terrible, but it was a good excuse to laugh together, and some things stuck with me.  One of those was from an episode of “The Red Green Show” (a Canadian comedy), in which the main character is explaining how to make some type of living space out of an old refrigerator.  “Don’t measure too carefully before you cut,” he advises, “because you’re going to need some cracks to get breathable air in!”

None of us are under much illusion that our long-term plans for this year will unfold in exactly the way we hope.  There is too much uncertainty.  But even the best of times have plenty of uncertainty to them.  As academics, we have the privilege to think long thoughts, and to work on projects that might not see fruition for several years.  But just because we are in a position to plan things out for several years, that doesn’t mean that it will work out as we expect.  And so…

For new students: grad school is a confusing place!  Plan to talk to faculty, and to get involved in research.  But realize you may not end up working with who you expect to, and you may find inspiration in a direction that you never even knew existed before coming here.

For old students: with graduation no longer on the infinitely-far-off horizon, you might well be worried about what comes next.  Network, make connections, plan — and realize that eventually you’re rolling the dice.  Have an idea where you want to go, but keep a broad awareness.  Applied mathematicians can go in an unusually wide number of directions, inside academia and beyond.

For students in-between: plan your research, your papers, your A and B exams.  And realize that it wouldn’t be research if we knew what we were doing, and you will almost surely have to abandon a plan or two in order to make progress.

And for all of you — plan to be gentle with yourself and with each other this fall.  Even if you sometimes fail in that plan, having made the plan in the first place might remind you to breath, cope, and lean on your friends when you need to.


No sermon this week, but did you know: On this day in 1894, the first summer meeting of the AMS was held at Brooklyn Polytech (now NYU Tandon).  A 126th anniversary isn’t quite as auspicious as a 125th, but it’s 2020 — let’s take what we can get!


That’s more than enough official business for one mail.  So I’ll wrap up this week with a snippet of another of Sandy Mack’s “sermons” from my undergrad days (from Dec 16, 1997):

How to Handle Stress:

  1. Pop some popcorn without putting a lid on it.
  2. When someone says, “Have a nice day,” tell them you have other plans.
  3. Make a list of things to do that you have already done.
  4. Dance naked in front of your pets.
  5. Tape pictures of your teachers on watermelons and launch them from high places.
  6. Walk to class backwards.
  7. Read the dictionary upside down and look for hidden meanings.
  8. Stare at people through the tines of a fork and pretend they are in jail.
  9. Make up a language and ask people for directions in it.
  10. Remember that when we next meet it will be a new year. With new chances for improvements. With new terrors. With new hope.

Have a great weekend.


It has been another terrible week in the news, and many of you are facing additional, personal hardships.  It’s a lot sometimes.  I’ve taken to dealing with that by sitting with our bunny rabbits and watching their antics (and sometimes they nibble on my toes).  It doesn’t make the world any better, but it at least cheers me up.

It promises to be beautiful weather here in Ithaca this weekend.  I hope those of you who are in town have the chance to enjoy it.  For those of you elsewhere, I still hope you have the chance to take a break this weekend.


When I was an undergraduate, I was part of the honors program at the University of Maryland.  At the time, the director was Maynard (“Sandy”) Mack of the English department.  He sent out an email about once a week, and always said the same thing at the start of the semester — and often in the middle of it:

I’ll always repeat at the start of each semester: in many ways we are our brother’s/sister’s keepers. If someone seems troubled, reach out. The worst you can get is yelled at, and you just might save someone’s semester…or life. Be kindly nosey, please. This perilous uncharted journey called life can be terrifically exciting in its freedom, and it can be overwhelming, in its freedom, too. Take care.

Yes, I still have those “sermon” emails, now from more than twenty years ago.  And I still think about them at times like this.  So obviously the message stuck with me, and I still find it helpful.  I hope the same thought is also helpful to you in these T-6 weeks until the fall.