## Magical Mathematics

One of these days, the Wall Street Journal will stop delivering the paper, which I stopped paying for back in October. But it keeps coming, and as long as it does, I’ll keep reading its book reviews. Like the lead review in yesterday’s book section of Magical Mathematics: The Mathematical Ideas that Animate Great Magic Tricks, by famed mathematicians Persi Diaconis and Ron Graham. And as always, when a book on mathematics receives a review from a major mainstream media outlet, I’ll be there to cover it.

From Princeton University Press’s description of the book:

Magical Mathematicsreveals the secrets of amazing, fun-to-perform card tricks–and the profound mathematical ideas behind them–that will astound even the most accomplished magician. Persi Diaconis and Ron Graham provide easy, step-by-step instructions for each trick, explaining how to set up the effect and offering tips on what to say and do while performing it. Each card trick introduces a new mathematical idea, and varying the tricks in turn takes readers to the very threshold of today’s mathematical knowledge. For example, the Gilbreath Principle–a fantastic effect where the cards remain in control despite being shuffled–is found to share an intimate connection with the Mandelbrot set. Other card tricks link to the mathematical secrets of combinatorics, graph theory, number theory, topology, the Riemann hypothesis, and even Fermat’s last theorem.Diaconis and Graham are mathematicians as well as skilled performers with decades of professional experience between them. In this book they share a wealth of conjuring lore, including some closely guarded secrets of legendary magicians.

Magical Mathematicscovers the mathematics of juggling and shows how the I Ching connects to the history of probability and magic tricks both old and new. It tells the stories–and reveals the best tricks–of the eccentric and brilliant inventors of mathematical magic.Magical Mathematicsexposes old gambling secrets through the mathematics of shuffling cards, explains the classic street-gambling scam of three-card monte, traces the history of mathematical magic back to the thirteenth century and the oldest mathematical trick–and much more.

Diaconis is the rare mathematician who has received extensive coverage in the popular press, thanks to his unusual background. As Alex Stone explains in yesterday’s WSJ review, “Mr. Diaconis has an especially unusual résumé for a mathematician. In 1959, at age 14, he ran away from home to study with the great 20th-century sleight-of-hand master Dai Vernon—a man who once fooled Harry Houdini with a card trick. After spending 10 years under Vernon’s tutelage, Mr. Diaconis returned home to New York and enrolled in night school, eventually earning a full ride to a Ph.D. program in mathematics at Harvard.” He visited Seattle just two months ago to give a major public lecture at the university, and has visited frequently before from his home base at Stanford.

Stone adds that

throughout the book, Messrs. Diaconis and Graham shuttle back and forth between magic and math, probing each trick for hidden mathematical insights and developing new magic based on what they find. In the process, they encounter a number of unsolved problems, some of which have prize money attached to them. It’s a fun ride, even if you don’t follow the nuances of every theorem and proof, and a refreshing change from the bombastic sort of magic one typically encounters on television.

I am intrigued by the notion that the Riemann Hypothesis and card tricks are related. I’ll have to get a copy of the book to learn more.

## Lunar Madness

[Dan Grayson, Tokyo, December 10, 2011]

Those of us on the west coast enjoyed a total lunar eclipse just before moonset yesterday morning, the last one until April 2014.

The entire lunar eclipse will be visible in East Asia, Australia, and the far western portion of North America that includes Alaska and Canada’s Yukon and Northwest Territories. The spectacle will last nearly three and a half hours, starting on Saturday at 4:45 a.m. Pacific Time.

Totality—when the full moon will be completely blocked from direct sunlight—will start at 6:05 a.m. PT and last until 6:57 a.m. PT.

We were discussing the eclipse at dinner with friends Friday evening. Would we wake up for it? Would we be able to see it without trees in the way? Jean mentioned that she would be up anyway, as she would be rowing. Plus, her location out on the water would provide unobstructed viewing. I imagined waking up and walking out to a clear area at the edge of the backyard with a good view to the southwest, but when the time came to set the alarm, I decided not to bother. I would either arise naturally or miss it.

At 5:55 a.m., I arose naturally. I looked at the clock, then noticed that the early morning moonlight that a full moon usually brings into the bedroom was missing. The eclipse was underway, on schedule, with totality ten minutes away. I couldn’t believe my luck. I got out of bed, got dressed, went down to the garage to get my coat and hat out of the car, got gloves from the closet, opened the backdoor, and headed out for total eclipse viewing.

Something didn’t seem right. I could see a faint glow to the southwest where the full moon must be. I couldn’t see the moon, which of course was the whole point. Then I realized what the problem was. I couldn’t see much else either, because it was cloudy.

Boy did I feel stupid. I completely forgot to look out the window to check for clouds before getting dressed. I could have done that and gone back to sleep.

Or maybe not. It was well before sunrise after all. Because of the darkness, I might not have been able to assess the nature of the cloud cover without going outside.

I went out again about 15 minutes later and then 30 minutes later, in case there was a break in the clouds, but there wasn’t. I had to content myself with my old friend Dan’s posting on Facebook at 5:34 a.m. PT of an eclipse photo he took from Tokyo. (See above.)

I’ll try again in a couple of years.

## Joke of the Week

I don’t anticipate that this will turn into a new Ron’s View feature. I’m trying it out in honor of my friend Paul, who dropped by my office Friday to chat before heading off for a conference in Stony Brook followed by holiday in his native New Zealand. In our conversation, it came up that Paul wanted to pass some information on to his father while they were on the phone, but his father didn’t have a pen at hand. This prompted Paul to tell his father a joke, which Paul then told me and which I am about to tell you. After delivering the joke, Paul suggested I put it on Ron’s View, but quickly had second thoughts, realizing it might not be classy enough for the neighborhood. Just this once, I will allow a lowering of the standards.

The joke is all about the punchline, so even if you forget the setup, you can create your own. With that in mind, and not entirely remembering Paul’s setup, I looked online last night and found many versions. As anticipated, the setup varies, but the punchline remains constant. Here’s my telling:

A busy doctor, nearing the end of a full day of appointments, is discussing a course of treatment with one of his patients. They agree to start the patient on a new medication and the doctor reaches into his jacket pocket for a pen. As he begins to write the script, he discovers that he is holding an anal thermometer.

“Damn,” the doctor exclaims, “some asshole has my pen!”

If you don’t like my setup, feel free to make up your own. Or do a search on “asshole has my pen” and study the many versions online. Some make the doctor a proctologist, which strikes me as overkill.

Thanks, Paul. Safe travels.