Category Archives: commerce

Pandemic blog 35: Updates

What’s going on with some of the topics previously covered?

Slimming: The initial weight loss reported slowed down, but hasn’t stopped, even though I started eating take-out from restaurants in July and have been doing so pretty regularly. Now at about 18 pounds below pre-pandemic weight. Why, I wonder? Is it really just the lunch out at work and the snack at the coffeeshop forgone?

Pandemic elections: 100,000 people in Dane County have already returned their absentee ballots for November. The city is setting up “Democracy in the Park” events where voters can turn in their ballots to city pollworkers; Republicans are trying to have those events declared illegal, because (this is me editorializing) they make it easy and convenient for people to vote whose votes they’d rather not see cast. There is a lot of noise about slowness of the mail, but it’s been fast here, and I mailed my ballot in; received by the clerk in just two days. The underlying worry here is that political actors will try to retroactively have legally cast ballots invalidated after Election Day, leaving voters with no recourse. The fact that mailed-in absentees are expected to be predominantly Democratic (only 44,000 ballots returned so far in Crucial Waukesha County) creates an obvious means of attack. I don’t really think that’ll happen but people are thinking about it under their mental breath.

Writing: The book is almost done! A draft is written, I’m going through and revising and putting in more endnotes now. To me it seems completely different from How Not To Be Wrong, while Dr. Mrs. Q says it seems exactly the same, which seems a kind of sweet spot: I can hope the people who liked the other book will like this one, while feeling for myself that I’m not putting out the same product again and again like a hack.

Impossible Meat: We’re still eating a lot of it! I have absolutely learned to read it as meat and no longer think of it as a substitute. But we’ve converged on using it exclusively in sauces; as a burger, it still doesn’t totally satisfy.

Smart Restart: After the big surge with the opening of classes, UW-Madison shut down in-person instruction for two weeks and put the two first-year dorms where cases were concentrated into isolation. The positivity rate on campus has dropped back down to around 1% and the campus outbreak doesn’t seem to have created sustained exponential growth in Madison’s general population; but it does seem to have brought our daily case load back up to where it was months ago, from which it is, again, only very slowly dropping. When R_0 is a little less than 1, even a brief bump up in prevalence can be very expensive in terms of long-term cumulative case numbers. Now we are starting football again. Is that smart? There won’t be any fans in Camp Randall (which means the economic catastrophe for local businesses of a year without a football season is going to happen unblunted.) Then again, there’s something hypocritical about me saying “Hell no, why take the risk” since I’ve been watching and enjoying baseball. The enjoyment of millions of fans actually does have value. MLB, because lots and lots of money is riding on this, has mostly kept its players and employees from suffering outbreaks. The Big Ten can probably do the same — if it cares to. What I worry about is this. By all accounts, in-person teaching hasn’t been spreading COVID either. But when we had in-person teaching, everyone felt things were more normal, and thinking things were more normal, they relaxed their social distancing, and that generated thousands of cases. There was indirect spread. Will football generate the same?

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Pandemic blog 16: links

We have mostly settled into a routine here. In the morning the kids have school. The 8th grade has a couple of on-the-screen meetings most days, but the 3rd grade has almost no real-time instruction, just assignments described in video clips by the teachers. That feels right to me; I’ve heard about kids in other cities asked to be in front of the laptop camera for six hours a day as if it made sense to hew to the usual schedule, and that sounds nuts to me. In the afternoon AB has “camp” for two hours where she does art projects with a counselor and a group of kids, mostly from here and there in the US, one from Costa Rica. CJ is still baking a lot — oatmeal raisin cookies yesterday.

It works, basically. I had a lot of ambitions for “things I’ve always wanted to do with the kids but we’re too overscheduled to get to them,” and most of those have been unrealized. I wanted us to play music together and record some tracks. I wanted CJ to do a coding project. I thought, being in the house all day, we could do some reorg and cleaning of the house. Those things didn’t happen (for the good reason that the kids didn’t actually want to do them.) On the other hand, both kids are doing AOPS courses, AB and I have learned to throw a Frisbee forehand, CJ and I watched The Mandalorian (much better overall than any of the last three movies). I always felt I should get into gaming with the kids and AB and I are now working our way through Pikuniku.

Of course, the fact that I can even think about opportunity as well as burden is because I am in the very lucky position of having a job that doesn’t go away during a pandemic, and I don’t have people in the house at high risk of serious illness, so I can safely accept the modest risk of infection that comes with shopping, taking walks, etc.

Nobody I know has died of this yet. Two people I know have lost parents, another an aunt, another a grandparent. I guess it depends what you mean by “know.” John Conway died of COVID last week. Is that somebody I know? He’s somebody I’d chat with when I was around the Princeton math department. His famous theorems are familiar, but in the round of admiration attending his death I learned one I didn’t know; given any six points in R^3, you can partition them into two groups of three in such a way that the resulting two triangles are linked. That’s cool, but the proof is even cooler — it turns out that the sum of the linking numbers over all 10 such partitions is always odd! My favorite kind of existence proof is “there are an odd number of these things so there aren’t zero of them.”

Our neighborhood bakery and our favorite breakfast place got PPP small business loans so they can continue to pay their employees for the next couple of months. That loan program ran out of money in 28 seconds or something but Congress is planning to fill the bucket with money again, they say. Campus is still closed but the undergraduates are rebuilding it in Minecraft. The governor has released a plan to start reopening schools and more businesses, once cases in Wisconsin start showing a consistent decline. That looked like it might happen soon, but now there’s a new outbreak in Green Bay, tied to spread in the meatpacking plants there. (Yes, non-Wisconsinites, that’s why the football team is called that.) The workers who keep the food supply going, just like the doctors and nurses treating patients, are unavoidably going to be exposed to a lot of risk, because, unlike me, they do work that can’t be done on a screen and can’t not be done.

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Pandemic blog 15: “lock them down”

Trader Joe’s on Friday: the first time I had to wait in line to get in the store. To maintain an appropriately low density, they don’t let a new shopper in until someone comes out. This week, about 90% of shoppers were masked. The people who weren’t were mostly college-age. The food supply still seems pretty normal; a few things, like butter, were out, but it’s Trader Joe’s — there’s always something they’re for some reason out of. I asked the store manager whether they were selling more beer than usual, and he said, beer, no, hard liquor, yes.

Large majorities in Wisconsin support the governor’s safer-at-home order, but there are always dissenters:

You might be surprised to hear I have some sympathy for this point of view, though he needs to be more broad with his lockdown; Waukesha County, where Menominee Falls is, has just as high a case rate as Dane does.

But it’s not crazy to imagine that COVID spread might be slower in less dense regions; maybe so much slower that the pandemic could be kept in check with less stringent suppression measures. Let’s posit that, eventually, we open schools and some businesses in rural Wisconsin before we do the same in Milwaukee. So this guy gets his wish.

My concern is this: he is not going to then say “It’s just like I said, I want to work and be productive, I’m glad I’m able to do so and I support strong relief measures for my fellow Wisconsinites in Milwaukee who have to stay home for the sake of public health.” No, I think that guy is going to say “Why should my taxes be paying somebody in Milwaukee to sit at home when I have to work?”

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Pandemic blog 3: usefulness, rules

One wants to feel useful. Of course, to an extent we are being useful by staying at home and not coming close to anyone outside the family. It’s incremental but somehow all this shared solitude generates a community spirit. We’re all in this, alone, together!

Of course when math is what you do you wish math were more useful, not in the true-but-abstract way we talk about math being useful, but useful today, in the face of what faces us. My colleagues Maria Chikina and Wes Pegden wrote up a model suggesting that we might do better to isolate younger people less than we are but older people much, much more. (Though whenever I leave the house I see older people are visibly out and about. Maybe it’s not up to “us.” Also, I am not really very much younger than older people anymore.) I was talking with Lior Silberman and Rachel Ward about pooling samples to mitigate what seems to be a shortage of COVID tests. Except nobody seems to really agree on whether there’s a shortage of tests or a shortage of administrative wherewithal to deploy the tests. Or maybe it’s swabs. There may not be enough swabs. And some people think we’re past the point in the United States where testing is useful, and maybe everybody should just treat themselves as if they’re infected. Anyway, they say you can test negative when you’re already infected but the viral load hasn’t built up enough for your sputum to set off the RNA detector.

Some rules everyone agrees on. If you must go outside, is to keep six feet of distance between you and anyone else. (Someone on Twitter asked whether they could still have sex, and got the answer: “If you can do it from six feet away, great!”) Wash hands for twenty full seconds, interlace the fingers to get the in-betweens, dig nails of one hand under the nails of the other to get any virus lurking under there. (Other sources recommend twisting the nails against the opposite palm in a circular motion for the same effect.) Some people are getting takeout, other people consider that risky. They say the virus can live 24 hours on cardboard, a few days on plastic and metal. Our neighborhood bookstore is closed for browsing but Joanne the proprietor is taking special orders. Two of AB’s came in so we stopped by to pick them up. I seemed more concerned about staying six feet from her than she was about staying six feet from me. I felt like a hero for having a no-touch credit card. She said the hard part was not really understanding when it was going to end. On the way home a guy with a stroller crossed the street so as not to pass us on the sidewalk.

The May conference in Germany on arithmetic statistics I was organizing for the Simons Foundation was postponed to an unnamed later date. Our moduli spaces conference here in Madison, which my student Soumya Sankar put a ton of work into, planned for next week, was cancelled too, of course. Just eight days ago we thought we were deciding whether or not to cancel it.

It’s so small in the big picture but I find myself moved by the small things I’m used to that are cancelled. United has shut down the direct flights from Madison to San Francisco and Los Angeles. I have to doubt they’ll come back soon, in the austere travel environment to come. The Isthmus, our alternative paper that’s been in press for 44 years, is shutting down. Maybe it would have gone out of business anyway. Most of those papers have.

Games played with kids: Mastermind 1. Monopoly 1. Big Boggle 4. Set 4. I am planning for Scrabble tomorrow.

I wrote to a friend on Monday, “I think we are going to be, like, playing 30 mins of Scrabble and then sniping at each other and I’ll relent and let AB watch Worst Cooks on the iPad. And I’ll look at Twitter and fume at all the academic parents who are like “it was so good for the kids and I to finally get the chance to act out Socrates’s dialogues, thanks coronavirus!!” So with that in mind I am somewhat embarrassed to say that I actually did a lot of math with AB today. Things I had been meaning to sit down and work through with her but didn’t find time when I didn’t have hours of time I needed to somehow fill. There are moments, lots of moments, where she rears back from instruction but today, for whatever reason, she was into it, and we just kept going. Area of isosceles triangles via Pythagorean theorem, then Heron’s formula — she liked very much the idea that they don’t teach it in regular geometry class. (They don’t, do they?) She is pleased with the word “semiperimeter.” In the context of areas, some approximation of square roots by decimals. Positive and negative exponents. And finally the Euclidean algorithm. In school they’re reducing fractions to simplest form and this was satisfyingly magical, to show how you can learn what to divide by without dividing.

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Los Angeles, November 2019

Actually, I arrived on October 31, but who can resist a gratuitous Blade Runner reference?

I was in town for the always-interesting meeting of the IPAM science board. Keep an eye on their schedule; there are great workshops coming up!

There was chaos and anger at LAX when I landed, because the airport just this week moved Lyft/Uber/taxi pickups offsite. For reasons I don’t fully understand, this has led to long waits for rideshare cars. For reasons I understand even less, people are waiting an hour for their Lyft to show up when the regular taxi stand is right there, and you can — I did — just hop in a cab with no wait and go. (Yes, a VC-subsidized Lyft is cheaper than a cab, if it’s not surge time. But the bus is cheaper still, and once you’re not saving time with the Lyft, what’s the point?)

So I got in my cab and went to the beach, and watched the sunset over the ocean. Clear view of a really nice Moon-Jupiter conjunction and Venus still visible down at the horizon. Last time I went to Dockweiler Beach I was all alone, but this time there were several groups of people in Halloween costumes around bonfires. That was probably the most Blade Runner thing about this trip and it wasn’t even November 2019 yet!

I have a first cousin in LA, and good luck for me — my first cousin’s first baby was born my first morning in town! So on Saturday after the meeting I got to go see my first cousin once removed on his second day alive. I haven’t seen a one-day-old baby in a really long time! And it’s true what they say; I both remember my own kids being that age and I don’t. It’s more like I remember remembering it. I thought I was going to have a lot of advice but mostly all I had to say to them was that they are going to be amazing parents, because they are.

The hospital was in East Hollywood, a neighborhood I don’t know at all. Walking around afterwards, I saw a sign for an art-food festival in a park, so I walked up the hill into the park, where there wasn’t really an art-food festival, but there was a great Frank Lloyd Wright mansion I’d never heard of, Hollyhock House:

As with most FLW houses, there’s a lot more to it than you can see in the picture. A lot of it is just the pleasurable three-dimensional superimposition of rectangular parallelipipeds, and that doesn’t project well onto the plane.

There were a lot of folks sitting on blankets on the hillside, even though there was no art-food festival, because it turns out Barnsdall Park is where you and your 20-something moderately hipster friends go to watch the sunset in LA (unless it’s Halloween, in which case I guess you dress up and build a bonfire on Dockweiler Beach.) Sunset:

Then I ate some Filipino food, since Filipino restaurants sadly don’t exist in Madison right now, and went back to my hotel and read MathJobs files.

My Lyft driver on the way back was a 27-year-old guy from Florida who’s working on an album. That’s no surprise; my Lyft driver yesterday was also working on an album. Your Lyft driver in LA, unless they are a comic, is always working on an album. (My Lyft driver yesterday was also a comic.) This ride was a little deeper, though. This guy was a first-generation college student who went to school out-of-state on a soccer scholarship, majored in biology, and thought about getting a Ph.D. but was too stressed out about the GRE. He said whenever he started studying for the math part he was troubled by deep questions about foundations. Pi, he asked me: what is it? How can anyone really know it goes on forever? For that matter, what about two? Why is there such a thing as two? He also wanted to be a perfusionist but sat in on an open-heart surgery and decided it wasn’t for him, not in the long term. He started asking himself: is biology what I really want to do? So he’s driving a Lyft and working on his album. He also told me about how he doubts he’ll be able to make a long-term relationship work because he doesn’t believe in sex before marriage (he said: “out of wedlock”) and how he had dabbled in Hasidic Judiasm and how he was surprised I was Jewish because I didn’t look it (“no offense.”) Anyway, it just made me think about how normal and maybe universal his existential doubts and worries are for a 27-year-old dude; but for an upper-middle-class 27-year-old dude from an elite educational background, those existential doubts and worries would be something to process while you continued climbing on up that staircase to a stable professional career. That would just be a given. For this guy, the world said “You’re not sure you want that? Fine, don’t have it.”

Now I’m in LAX about to go get on the flight home to Madison, the direct flight we so gloriously now have. The last time I was in this LAX breakfast place, there was a big tumult around somebody else eating there and I realized it must be a celebrity, but I didn’t recognize him at all, and it turned out it was Gene Simmons. In LA people know what Gene Simmons looks like without the Kiss makeup! I do not. For all I know he could be in here right now. Are you here, Gene Simmons?

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In which I almost waste four dollars at Amazon

Instructive anecdote. I needed a somewhat expensive book and the UW library didn’t have it. So I decided to buy it. Had the Amazon order queued up and ready to go, $45 with free shipping, then had a pang of guilt about the destruction of the publishing industry and decided it was worth paying a little extra to order it directly from the publisher (Routledge.)

From the publisher it was $41, with free shipping.

I think it really did used to be true that the Amazon price was basically certain to be the best price. Not anymore. Shop around!


If I have caught a foul ball it is only by standing on the shoulders of giants

“Combined cap and baseball mitt,” A patent by Richard Villalobos, 1983.


This is meant for fans, not players. The idea is that if a foul ball comes towards you, you may not have time to grab a glove you’ve stashed at your feet. Rather, you quickly slip your hand into the cap-mounted glove and snag the foul with your hat still attached to the back of your hand.

What is the median length of homeownership?

Well, it’s longer than it used to be, per Conor Dougherty in the New York Times:

The median length of time people have owned their homes rose to 8.7 years in 2016, more than double what it had been 10 years earlier.

The accompanying chart shows that “median length of homeownership” used to hover at  just under 4 years.  That startled me!  Doesn’t 4 years seem like a pretty short length of time to own a house?

When I thought about this a little more, I realized I had no idea what this meant.  What is the “median length of homeownership” in 2017?  Does it mean you go around asking each owner-occupant how long they’ve lived in their house, and take the median of those numbers?  Probably not:  when people were asked that in 2008, the median answer was 10 years, and whatever the Times was measuring was about 3.7 years in 2008.

Does it mean you look at all house sales in 2017, subtract the time since last sale, and take the median of those numbers?

Suppose half of all houses changed hands every year, and the other half changed hands every thirty years.  Are the lengths of ownership we’re medianning half “one year” and half “30 years”, or “30/31 1 year” and 1/31 “30 years”?

There are about 75 million owner-occupied housing units in the US and 4-6 million homes sold per year, so the mean number of sales per unit per year is certainly way less than 1/4; of course, there’s no reason this mean should be close to the median of, well, whatever we’re taking the median of.

Basically I have no idea what’s being measured.  The Times doesn’t link to the Moody’s Analytics study it’s citing, and Dougherty says that study’s not public.  I did some Googling for “median length of homeownership” and as far as I can tell this isn’t a standard term of art with a consensus definition.

As papers run more data-heavy pieces I’d love to see a norm develop that there should be some way for the interested reader to figure out exactly what the numbers in the piece refer to.  Doesn’t even have to be in the main text.  Could be a linked sidebar.  I know not everybody cares about this stuff.  But I do!




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I guess Caffe 608 was in trouble

Eight years after I wondered whether the arthouse cinema / cafe in Hilldale could really make a go of it, Sundance 608 is getting bought out by AMC.  I have really come to like this weird little sort-of-arthouse and hope it doesn’t change too much under new management.  It’s a sign of my age, I guess, that I still think of “movie at the mall” as an entertainment option I want to exist.  It’s my Lindy Hop, my vaudeville, my Show of Shows.

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Mathematicians becoming data scientists: Should you? How to?

I was talking the other day with a former student at UW, Sarah Rich, who’s done degrees in both math and CS and then went off to Twitter.  I asked her:  so what would you say to a math Ph.D. student who was wondering whether they would like being a data scientist in the tech industry?  How would you know whether you might find that kind of work enjoyable?  And if you did decide to pursue it, what’s the strategy for making yourself a good job candidate?

Sarah exceeded my expectations by miles and wrote the following extremely informative and thorough tip sheet, which she’s given me permission to share.  Take it away, Sarah!



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