
Read about "Mouthwatering Math". (Photo: "Strawberries with tiles of coral and cocoa," by Mercedes Siles Molina and Chef José Carlos Garcia, photograph by Pedro Reyes Dueñas. Courtesy Mercedes Siles Molina.)



Mike Breen and Annette Emerson
Public Awareness Officers
paoffice at ams.org
Tel: 4014554000
Fax: 4013313842 

Alexander Grothendieck, 19282014
Alexander Grothendieck died on November 13, 2014. His obituary in the next day's New York Times was titled: "Alexander Grothendieck, Math Enigma, Dies at 86," referring probably both to the bewildering power of his mathematical genius and to the mystery with which he cloaked his last years, living in seclusion in a village in the Pyrenees; he died nearby. The Times writers, Bruce Weber and Julie Rehmeyer, set the stage for their account of Grothendieck's work: "Algebraic geometry is a field of pure mathematics that studies the relationships between equations and geometric spaces. Mr. Grothendieck was able to answer concrete questions about these relationships by finding universal mathematical principles that could shed unexpected light on them." They come back to this organizing principle of Grothendieck's mathematics later in the obituary, speaking of his contribution to the proof of the Weil Conjectures: "But characteristically he did not attack the problem directly. Instead, he built a superstructure of theory around the problem. The solution then emerged easily and naturally, in a way that made mathematicians see how the conjectures had to be true. He avoided clever tricks that proved the theorem but did not develop insight. He likened his approach to softening a walnut in water so that, as he wrote, it can be peeled open 'like a perfectly ripened avocado.'" And they include this quotation from his memoir Reapings and Sowings:

"If there is one thing in mathematics that fascinates me more than anything else (and doubtless always has), it is neither 'number' nor 'size,' but always form. And among the thousandandone faces whereby form chooses to reveal itself to us, the one that fascinates me more than any other and continues to fascinate me, is the structure hidden in mathematical things."
The Times also published, on November 25, "The Lives of Alexander Grothendieck, a Mathematical Visionary" by Edward Frenkel. The essay devotes equal space to Grothendieck's mathematical accomplishments (Frenkel actually gives an example of what algebraic geometry is about) and to his equally obsessive work on human rights and environmental degradation. Frenkel connects the two lives: "Though one might ask if there are any realworld applications of his work, the more important question is whether having found applications, we also find the wisdom to protect the world from the monsters we create using these applications. Alas, the recent misuse of mathematics does not give us much comfort." He links to the page Grothendieck's nonmathematical writings, which itself links to issues of the newsletter Survivre et Vivre, published in 197073. There, Frenkel tells us, "one can see Grothendieck confronting the world's ills with his signature rigor and passion."
Le Monde ran the headline, on November 14, "Alexandre Grothendieck, the greatest mathematician of the XX century, has died." Their obituary (by Stéphane Foucart and Philippe Pajot) contains many biographical details, including the legend of the fourteen problems:

"Looking for a thesis problem, he is sent to meet Laurent Schwartz and Jean Dieudonné. ... The two great mathematicians give the young student a list of fourteen problems which they consider a vast program of research for the years to come, and ask him to choose one. A few months later, Alexandre Grothendieck is back: he has solved them all."
And this quote from his student Pierre Deligne: "He was unique in his way of thinking. He had to understand things from the most general point of view possible; once things had been settled and understood in that way, the landscape would become so clear that proofs seemed almost trivial." Le Monde online has a sixminute video in which the mathematician and historian JeanMichel Kantor gives an eloquent portrayal of Grothendieck and his scientific impact, including a reading from Grothendieck's text of the entire walnutavocado simile mentioned in the Times. The title of the video, "Grothendieck's ideas have penetrated the subconscious of mathematicians" is a quote from Pierre Deligne. Le Monde also gives a link to the text of the letter Grothendieck sent them in 1988, explaining his refusal of the Crafoord Prize.
Also available on the web is A country known only by name, written by his former associate Pierre Cartier: a detailed overview of Grothendieck's scientific work, along with a firstperson account of some of the stormier moments that punctuated his withdrawal from academic and scientific life. [My translations, except for those quoted; Cartier's text has been translated into English, but Reapings and Sowings, as far as I know, unfortunately, has not. TP]
New Zealand robin arithmetic
An article in press in Behavioural Processes was picked up by the website Nature World News ("Birds Can Count: How We Know It," November 18, 2014), on the conservation website The Dodo (Birds Literally Do The Math When Their Mate's Behavior Doesn't Add Up) and featured in a video on the "Science Take" webpage of the New York Times (by David Frank, November 17, 2014). The article is "Addition and Subtraction in wild New Zealand Robins," by Alexis Garland and Jason Low (Victoria University, New Zealand). Garland and Low presented robins in the wild with a "Violation of Expectancy" (VoE) task designed to test their discrimination of number, and changes in number. The test used a box with two compartments, similar in design to those used in disappearingpenny "magic" tricks; instead of penny/nopenny, different numbers of mealworms were placed in the compartments, as follows: . "... the upper compartment of the VoE box ... was first baited out of view (pretrial) with the final quantity of prey found by the robin, then the trial was initiated, and a quantity of prey added (and in some cases subtracted) from the apparatus within view of the robin ..." Note within view of the robin. The worms go into or are taken from the lower compartment. Then a leather disc is placed over the box and the upper compartment is secretly slid in over the lower. " ... finally the experimenter stepped back, and the robin was allowed to uncover the apparatus and access the (now visible) upper compartment." "Robins spend the majority of their time hunting on the forest floor, turning over leaves in search of insects ... . As such, pulling the leather flap from a small wooden platform was a very simple extension of their natural behaviour, adopted typically within a very short period of exposure to the materials (well under 30 min, on average)."
"Robins were shown 8 different hiding events in randomised order, and found 4 numerically congruent and 4 numerically incongruent" as itemized in this table:
Congruent

Incongruent

$1+0=1$

$1+1\neq 1$

$1+1=2$

$20\neq 1$

$21=1$

$30\neq 2$

$31=2$

$31\neq 1$

The authors measured robins' activity in the period after the flap was lifted. "A video analysis was performed looking at 2 different dimensions of response behaviour: First, search duration  the total amount of time the robin spent actively examining the apparatus (looking closely into, at or under it, pecking at it, hopping onto or around it) or leather cover (pulling at it with their beak, flipping it over, standing on it, looking closely at it). Second, pecking frequency  the number of times the subject pecked with its beak at any part of the apparatus."
The results of the described experiment: average response for search time(s) and for number of pecks compared between the "congruent" trials (green; see table above) and the "incongruent" trials (orange). Error bars show $\pm 1$ Standard Error. Image adapted from Garland and Low.
As the authors report: "... on average, robins measured higher on both behavioural measures in incongruent than congruent trials." And they conclude: "... robins appear to be able to respond to protonumerical summation and subtraction involving small ($<4$) quantities." As to where mates come into the picture, "In addition to hunting and caching insects, pairs also frequently pilfer prey from mates."
"Solving for XX:" women and math in the Berkeley Daily Planet
Jonathan Farley contributed the Feature "Solving for XX" to the Berkeley Daily Planet for October 23, 2014. The highlight is an interview with Danica McKellar, the actress with the math degree from UCLA and the author of, inter alia, Kiss My Math: showing prealgebra who's boss. McKellar: "The problem isn't that girls don't do math as well as boys. The problem is that, in spite of good test scores, girls don't see themselves as capable of doing math as well as boys. So as soon as they hit a stumbling block, instead of seeing it as a temporary obstacle that can be overcome, they more often see it as evidence of what they've 'known' all along  that they don't belong in math. That it's not really 'for them.' ... the only way around it is to do what we can to break stereotypes, and to bombard girls with the opposite of the limiting female characters they get from most media: positive role models to show them, 'You have every potential within you. Develop your brain. You belong!'"
Knots in physics
"Get Knotted: They've been practising for ages, but physicists are finally learning how to tie knots in things," by Leonie Mueck, ran in the New Scientist on October 4, 2014. The short article surveys physicists' involvement with knots, starting back in the 19th century with Peter Tait's idea that atoms might correspond to infinitesimal looped vortices in the "lumeniferous aether," with different elements corresponding to different knots. This led to the first knot tables, but was a dead end in physics. Mueck gives a quick survey of recent developments, which include:
Tony Phillips
Stony Brook University
tony at math.sunysb.edu

Math Digest includes posts throughout each month by Anna Haensch (Drexel University) and Ben PittmanPolletta (Boston University). These earlycareer mathematicians provide their unique insights (and occasionally videos, interviews and podcasts) on mathrelated topics recently covered by the media.
Recently posted:
From Rubber Sheets to Happy Apps, Discover Tunes in to the Top Math Stories of 2014, by Anna Haensch
The JanuaryFebruary 2015 issue of Discover Magazine features the top 100 science stories of 2014. Included among them are 5 stories about boundary breaking mathematics and mathematicians that have taken center stage this year.
One such boundary breaker was Maryam Mirzakhani, who became the first woman ever to win the Fields Medal at this year’s ICM (International Congress of Mathematicians, held in Seoul) . Her work is in geometry and hyperbolic surfaces and Etienne Ghys of the Fields Medal committee describes it as "amazing formidable work." Her life and work were beautifully described by Quanta Magazine.
Breaking through a layer of mold, a team of researchers found a set of ancient bamboo strips which appear to be the world’s oldest calculator. The set belongs to a larger collection of 2,500 strips which are marked with numbers 1/2 to 90 and could have been used just like multiplications tables.
At Brown, a team came up with a mathematical formula to describe how rubber surfaces fold. Their equation can predict precisely how a material will fold given its composition and stiffness, and how much pressure will be need to flatten it out. Obviously this is a breakthrough for materials engineers, but people in the medical field can also use this to analyze what happens to the skull in a traumatic head injury. The original article appeared in the Proceedings of the Royal Society.
Another captivating story came out of the University College London, where researchers discovered that the key to happiness is lowered expectations. In small experiments conducted in the lab, and larger ones conducted using a smart phone app, they found that people’s happiness was highest when they just got more than they expected. The original article appeared in PNAS (Proceedings of the National Academy of Sciences of the United States of America).
A final story is on number theorist Ken Ono and his collaborators, who made a key discover about the beautiful and captivating RogersRamanujan identities last summer. According to Ono, he and his collaborators Michael Griffin and Ole Warnaar were studying these identities, and “found a framework that shows why they’re true.…They turned out to be two golden nuggets that suggested the existence of a whole mother lode of identities out there.”
To pick the top story of the year, Discover is asking readers to vote. Go here to cast your vote in the second round (by December 10), because wouldn’t it be cool if the number one science story of the year was about math!
See "100 Top Stories of 2014," Discover, JanuaryFebruary 2015. (Access to the full articles online requires a subscription.)
 Anna Haensch
Also now on Math Digest: Optical illusions, mathematicians at the televised Breakthrough Prize award ceremony, Terence Tao on The Colbert Report, illusions, hipsters, mouthwatering math, ...
Citations for reviews of books, plays, movies and television shows that are related to mathematics (but are not aimed solely at the professional mathematician). The alphabetical list includes links to the sources of reviews posted online, and covers reviews published in magazines, science journals and newspapers since 1996.
