Miskatonic University Press

6/π²

mathematics podcasts

I really enjoyed the latest episode of the My Favourite Theorem podcast, with Jayadev Athreya.

JA: So when trees are planted by a paper company, they’re planted in a fairly regular grid. So imagine you have the plane, two number lines meeting at a 90 degree angle, and you have a grid, and you plant a tree at each grid point. So from a mathematician’s perspective, we’re just talking about the integer lattice, points with integer coordinates. So let’s say where I’m standing there’s a center point where maybe there’s no tree, and we call that the origin. That’s maybe the only place where we don’t plant a tree. And I stand there and I look out. Now there are a lot of trees around me. Let’s say I look around, and I can see maybe distance R in any direction, and I say, hm, I wonder how many trees there are? And of course you can do kind of a rough estimate.

Now I’m going to switch analogies and I’ll be working in flooring. I’m going to be tiling a floor. So if you think about the space between the trees as a tile and say that has area 1, you look out a distance R and say, well, the area of the region that you can see is about πR², it’s the area of the circle, and each of these tiles has size 1, so maybe you might guess that there are roughly πR² trees. That’s what’s called the Gauss circle problem or the lattice point counting problem.

But you can’t see every tree in all directions, because some are behind each other in your line of vision.

JA: A point (m,k) is visible if the greatest common divisor of the numbers m and k is 1. That’s an elementary exercise because, well maybe we’ll just talk a little bit about it, if you had m and k and they didn’t have greatest common divisor 1, you could divide them by their greatest common divisor and you’d get a tree that blocks (m,k) from where you’re sitting…. We call these lattice points, they’re called visible points, or sometimes they’re called primitive points, and a much trickier question is how many primitive points are there in the ball of radius R, or in any kind of increasingly large sequence of sets…. And miraculously enough, we agreed that in the ball of radius R, the total number of trees was roughly the area of the ball, πR². Now if you look at the proportion of these that are primitive, it’s actually 6/π².

This is another way of talking about the “probability of coprimality” (see coprime integers on Wikipedia): pick any two integers at random, and the probability that they are coprime (have no prime factors in common) is 6/π². Primes and pi coming together! Beautiful.

Sorting LCC call numbers in R

code4lib r

Here’s the easiest way to sort Library of Congress Classification call numbers in R:

call_numbers <- c("QA 7 H3 1992", "QA 76.73 R3 W53 2015", "QA 90 H33 2016", "QA 276.45 R3 A35 2010")
library(gtools)
mixedsort(call_numbers)
## [1] "QA 7 H3 1992"          "QA 76.73 R3 W53 2015"  "QA 90 H33 2016"        "QA 276.45 R3 A35 2010"

gtools is part of standard R. The docs says about mixedsort and mixedorder:

These functions sort or order character strings containing embedded numbers so that the numbers are numerically sorted rather than sorted by character value. I.e. “Asprin 50mg” will come before “Asprin 100mg”. In addition, case of character strings is ignored so that “a”, will come before “B” and “C”.

(I don’t know why “Aspirin” is misspelled.)

If you have a data frame (df) with column call_number then you would use mixedorder to sort the whole thing by call number thusly:

df[mixedorder(df$call_number), ]

I asked about this on Stack Overflow and on the Code4Lib mailing list last July, then I went on vacation and sort of forgot about it. Nine months later, I thanked Li Kai, who pointed me to a Stack Overflow that solved my problem and let me then answer my own question.

Unrelated library sign.
Unrelated library sign.

Let's Encrypt

unix

A quick note to say I had no idea Let’s Encrypt is so easy to use. I followed these instructions, but the EFF’s Certbot gives instructions for many sorts of systems.

I thought the tool would generate some confusing configuration file I’d need to edit and move and tweak, but all I had to do was this (on an Ubuntu system where I host a web site): three commands to install the tool, then one to say, “Make this site work with HTTPS.”

sudo add-apt-repository ppa:certbot/certbot
sudo apt-get update
sudo apt-get install python-certbot-apache
sudo certbot -d hostname.library.yorku.ca

I answered one or two yes/no questions and then it just worked.

This is really admirable work. My congratulations and thanks to everyone involved.

Two stories about Betty at the library

archie libraries

There are two back-to-back Riverdale Public Library stories about Betty in B&V Friends Jumbo Comics Digest 258 (March 2018).

First is “Keep Those Library Doors Open,” written by George Gladir, pencilled by Jeff Shultz, inked by Al Milgrom, lettered by Jack Morelli and coloured by Barry Grossman. It originally appeared in Betty and Veronica Double Digest 186.

Here’s the first panel, where Betty, Veronica and Nancy ask the librarian, Ms. Alvarez, about the situation.

First panel of Keep the Library Doors Open
First panel of Keep the Library Doors Open

This is a branch library, not the central one (in fact this is the first time I’ve seen a mention that the Riverdale Public Library has more than one branch). Mr. Lodge knows what’s going on, as Veronica learns: “Our city’s tax revenue is down drastically—and the special bond issue to fund the library was voted down! However, our city’s main library will remain open.” Veronica is not satisfied: “It won’t be enough! I’m told demand for library services has never been greater!”

They all go to city council (apparently Mr. Lodge is powerful enough in Riverdale to have an item immediately added to the agenda), where Ms. Alvarez pleads for more time. “All we ask is the opportunity to try some measures to stall the closing of our library … like reducing hours and recruiting volunteers!” It works: a month later, because of the cost-cutting measures, the library is allowed to stay open.

This kind of situation happens regularly, sad to say, but in a real city there would be more long-term planning (a city council wouldn’t allow one branch to stay open for one more month on the spur of the moment) and the chief librarian would also be involved. However, for the sake of the story, narrowing the focus works well. Of course, it’s great to see a story of public activism successfully keeping a library open.

On the other hand, the solution presented is not sustainable in the long term. A better one would be to raise taxes, especially on families like the Lodges.

The second story is “Check It Out,” written by Kathleen Webb, pencilled by Stan Goldberg, inked by John Lowe and lettered by Bill Yoshida (there is no colouring credit). I’m not sure when it originally appeared, but it looks like the 2000s. (This is not the same as another “Check It Out!”, which I haven’t seen, where Archie and Reggie join the library club because there’s an attractive librarian.)

This is a delightful story all about a wonderful visit Betty takes to the library. Unlike the “Keep Those Library Doors Open,” here Veronica doesn’t care about the library at all: she says, “I just don’t see what she gets in that mausoleum for nerds!”

Panel from Check it Out
Panel from Check it Out

Betty searches the library catalog (an OPAC) for books to help with a school assignment, then notices some new fashion history books and some new style magazines. She uses the library computers to do research on the web, too. While she’s working the librarian, Ms. Dewey, comes over and does some reader’s advisory.

Another panel from Check it Out
Another panel from Check it Out

Next, Betty sees a DVD of a movie Archie hasn’t seen, and takes out it and a cookbook so she can make a new dish for an evening together. She seems some little kids she babysits and reads them a story, then gets a CD, then runs into a tough-looking motorcyclist she knows who happens to be getting Crocheting Doilies Made Easy, which he claims is for his mother.

After Ms. Dewey checks out her books, Betty says, “There’s nothing like an afternoon at the library!” This is great story about all the things public libraries have to offer.

Easy Reader

libraries

When I was a little kid in the early ’70s, I liked watching The Electric Company. My favourite character was Easy Reader, and even though Morgan Freeman has had a great career since then, that’s how I always think of him. I just realized today that Easy Reader must have been a play on Easy Rider. I didn’t clue in at the time, but after all, I wasn’t even in grade one yet.

Here’s Easy chatting up a librarian and having fun with words:

Play It Again

music reviews

I highly recommend Play It Again: An Amateur Against the Impossible, by Alan Rusbridger. It’s a delightful book, full of fascinating detail, and will get you thinking about music in new ways.

Cover of Play It Again
Cover of Play It Again

Rusbridger was editor of The Guardian from 1995–2015. He’d played the piano when he was young, then stopped. In his forties he got back into it. In the summer of 2010 he decided to tackle Frédéric Chopin’s Ballade No. 1 in G minor. It’s a very difficult piece, but he decided to learn it over the next year so he could perform it the next summer. The book is the story of that year and a bit more.

(See Play It Again by Alan Rusbridger – review by Iain Burnside for a full review of the book (in the Graun) including a video with Rusbridger talking about the book and playing some of the piece.)

Now, being editor-in-chief of The Guardian is an incredibly busy and stressful job in any year, but the year in question was also the year of major Wikileaks releases and the British phone hacking scandal, in both of which The Guardian played a leading role. What’s more, at one point Rusbridger had to fly to Libya to negotiate the release of a Guardian reporter who had crossed the country’s border illegally and then been arrested.

All through this, when he can, when he’s not working sixteen- or eighteen-hour days (and even sometimes when he is), he’s grabbing twenty minutes in the morning to practice, and taking lessons when he can.

Some of the book is about his life as an editor, which is astonishing stuff, but most of it is about playing the piano, and the amount of detail is remarkable. I had no idea people spent so much time thinking about and practicing one bar in a score. One bar!

Along the way Rusbridger talks to several pianists about the piece. I think my favourite interview was in New York with Charles Rosen, who lived in the same apartment from when he was six to when he died. Rosen studied under Moriz Rosenthal, who studied under Liszt … who studied under Chopin.

The story of his study and practice of the piece is wonderful, but I was also struck by the rest of his musical life. He often gets together with other amateurs and semi-professionals (including Richard Sennett) to play chamber pieces or bash their way through two-piano eight-hands transcriptions of symphonies. The thrill and joy of playing such music with friends comes to life in his writing, and if, like me, you can’t play the piano, you’ll wish that at least you could sit in on a night like that.

Research data management librarian job posting at York University

code4lib yorku

Research data management librarian wanted at York University Libraries in Toronto, where I work.

York University Libraries (YUL) seeks a dynamic and innovative individual with strong leadership potential to advance York University Libraries’ research data management portfolio in support of the research community across campus.

The successful candidate will be a member of the new Research and Open Scholarship division and will report to the Director for Open Scholarship. The incumbent will lead the development of a research data management program on campus and will coordinate ongoing support in this area within a team-based environment. The incumbent will work collegially with departmental members to advance the wider responsibilities of the Open Scholarship Department.

I’m not on the search committee and am happy to answer any questions I can from anyone interested in applying, by email or even by phone. They’re looking for someone who knows RDM and also can handle chemistry and other physical sciences.

Pay at York is good. I’d guess someone five years out of library school would get over $90,000 CAD. We have good benefits, time for (and expectations about) research, and of course the subway comes right on campus now. After six years the person will be up for continuing appointment (what we call tenure) and then get a sabbatical year. On the bad side, of course, CUPE 3903 is on strike right now.

YUL is going through a restructuring and this position will be in a new department. Anyone taking the job should ask serious questions about how the department will work and what support they will have in the role, but all in all I think the new structure will work pretty well and there is a lot of promise ahead.

Non-Canadians are welcome to apply. The way it works, any qualified Canadian trumps any non-Canadian, even if the non-Canadian is actually better, but don’t let that stop you from applying. The bigger the pool the better for us, of course, but with specialized knowledge like this, you never know what will happen or how many Canadians will apply.

Anyone whose career has taken unusual turns or had to take some time out (for parental or caregiver leave or something else) should mention that in the cover letter, and the search committee will consider it.

You Are

john.cage listening.to.art marcel.duchamp

I just finished Begin Again: A Biography of John Cage, by Kenneth Silverman, which is a fine account of the amazing entirety of John Cage’s incredible life. I agree with John Adams’s review where he says, “Silverman is concerned less with parsing Cage’s aesthetics than he is with carefully recounting the life, which he does in a matter-of-fact, occasionally plodding manner,” but also where he says, “Cage himself is revealed in a richly shaded and profoundly human portrait” and that the book shows “Cage’s enormous capacity for work, together with his exceptional self-discipline as an artist (something learned from Schoenberg) and his willingness to approach every new challenge with a ‘beginner’s mind.’ For this alone it is a book worthy of being read by anyone, young or old, who is faced with the daunting task of a new creative beginning.”

Cover of Begin Again
Cover of Begin Again

Every page is filled with remarkable details and incidents, like p. 41 for this in late 1940 when Cage is raising money for his Center for Experimental Music:

He played some of his percussion records for the artist Diego Rivera, who became “very enthusiastic,” Cage said; Rivera spoke to influential people on behalf of the Experimental Center and “referred” him to Charlie Chaplin.

These two names appear out of nowhere. However, two pages later we read, “He learned that people of Chaplin’s celebrity were ‘very difficult to get to.’” No doubt! Still, pretty good for a 28-year-old.

About Cage’s friendship with Marcel Duchamp (p. 228):

Their new friendship pleased Duchamp no less than Cage. “We’re great buddies,” he told an interviewer; “we have a spiritual empathy and a similar way of looking at things.” On many key points their aesthetic thought matched.

Cage once joined Duchamp and his wife on vacation in Spain, where the Duchamps regularly hung out with Salvador Dalí and his wife Gala:

One time at Cadaqués, Duchamp persuaded Cage to accompany him and Teeny to visit Salvador Dalí, living in a group of connected fishermen’s shacks at nearby Port Lligat. Cage disliked Dalí’s paintings, and in person disliked the painter no less. Dalí showed them a huge painting that Cage though “vulgar and miserable.” And the artist talked and talked, he said, “as though he was the king.” He found it hard to understand Duchamp’s admiration for Dalí.

I was particularly struck by this (p. 276) work with William Anastasi:

But in 1977 he came across a painter he had briefly met a decade earlier who became his lifelong chess partner—the innovative conceptual artist William Anastasi (1933–). At the time, Anastasi was seeking a narrator for his performance piece You Are, to be presented at a gallery show of his large silkscreened paintings. Allen Ginsberg and some others had turned him down. So Anastasi’s partner, Dove Bradshaw, a young artist working in clay sculpture and photography, suggested Cage.

The couple spoke with Cage at his Bank Street apartment. Anastasi explained that Cage’s role in You Are would be to report what sounds he heard in the gallery. Cage liked the idea and agreed to appear. (As he later did, telling of rubber-soled shoes, a coat button scraping the wall, someone sneezing: “do you have a cold?” he asked the sneezer; “do you need some kleenex?”)

In Listening to Art, there is no narrator.

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