Visit our AMS COVID19 page for educational and professional resources and scheduling updates
On the U.S. IMO team, by Mike Breen
Photo, left to right: Michael Kural, Yang Liu, Allen Liu, Ryan Alweiss, Shyam Narayanan, and David Stoner, courtesy of the MAA.

The U.S. team finished first at the 2015 International Mathematical Olympiad (IMO) in Chiang Mai, Thailand, edging the team from China 185181. The six team members (pictured and identified at left) were coached by PoShen Loh of Carnegie Mellon University, who said, "This is a huge deal." Indeed it is, and it was recognized by the White House in a tweet: "Go Team USA! America took first place in the International Mathematical Olympiad for the first time since 1994." In the article, Loh also gives a sense of the atmosphere at the IMO, contrasting it with that at major sports events, which often feature intense rivalries and occasional cheating, "It's the exact opposite of backstabbing,... The coaches are always the same. We are all friends. It's very collegial. We are essentially going after the same goal, which is to drive the whole world up." In the Los Angeles Times article (linked to below), Loh added, "As time goes on, we hope that more people will understand that math is much more than people thought." Five of the six members of the U.S. teamRyan Alweiss (Bergen County Academies, NJ), Allen Liu (Penfield Senior High School, NY), Yang Liu (Ladue Horton Watkins High School, MO), Shyam Narayanan (Blue Valley West High School, KS), and David Stoner (South Aiken High School, SC)earned gold medals, and the sixthMichael Kural (Greenwich High School, CT)won a silver medal, one point shy of gold. Three of the sixMichael, Shyam, and Davidare former contestants in the AMS math game for high school students, Who Wants to Be a Mathematician. The six were selected based on their performance in competitions organized by the MAA. 
Most of the previous summary is based on the story from The Washington Post. In the other coverage below: Erickson focuses on coach PoShen Loh, who went to high school in Madison, WI; Gates writes about Seyoon Ragavan of Australia, who won a gold medal and helped the team finish sixth overall, its highest finish ever; Chakrabarti interviews coach Loh, and team members Ryan Alweiss and Yang Liu; and the CTV story is about Alex Song, of the Canadian team, who earned a perfect score at the IMO for his paper.
See
"Winning formula: USA tops International Math Olympiad for first time in 21 years," by Michael E. Miller. The Washington Post, 18 July 2015,
" Former Memorial High School math whiz coaches Team USA to big international win," by Doug Erickson. Wisconsin State Journal, 18 July 2015,
"A young mathematics whiz from Sydney has won gold at an International Olympiad," by Alyshia Gates. Special Broadcasting Service, 22 July 2015,
"U.S. Takes Home Gold ... In Math," by Meghna Chakrabarti. WBUR, 24 July 2015, "U.S. wins gold at International Math Olympiad for first time since 1994," by Natalie Schachar. Los Angeles Times, 26 July 2015, and
"Canadian math whiz wins international competition," by Liam Casey. CTV, 27 July 2015.
"The U.S. International Math Olympiad Victory Was a Predictable Miracle," by Peter Rugg. Inverse, 25 September 2015.
 Mike Breen
On John H. Conway, by Claudia Clark
In this lengthy article, the writer describes the life and work (or play?) of mathematician John Conway, beginning with his trip in 1956 to Cambridge University as an incoming undergraduate student, and ending with his current work. Roberts, who has written a recent book on Conway, discusses his major discovery of the Leech lattice's symmetry in the late 60s, his discovery of surreal numbers, his development of the "The Game of Life," and his recent creation of "The Free Will Theorem." She also talks at length about Conway's creation of his "doomsday rule,"an algorithm Conway created for determining the day of the week for any dateand the way he has used this game to test himself as he has gotten older. The article emphasizes Conway's lifelong love of playing and inventing games, some of which have led to his remarkable discoveries. Roberts writes: "For Conway it is mathematics that allows him to clear away the clouds of reality. As he put it, 'Math was always there for me.' It is the realm where he finds solace and infinite unadulterated pleasure. He's retired, but he keeps on playing, and as he himself noticed, he's now being more productive than ever." (Photo of John Conway and Siobhan Roberts, taken by Annette Emerson at the Bridges Math & Arts Conference in Baltimore, MD, July 2015.)
See "The world's most charismatic mathematician," by Siobhan Roberts. The Guardian (UK), 23 July 2015.
 Claudia Clark
On using math to analyze leads in sports, by Allyn Jackson
Want to know what size lead a basketball team needs in order to have a 90 percent chance of winning in the remaining seconds of the game? Just take the square root of the number of remaining seconds and multiply by 0.4602. That's the conclusion of work by Aaron Clauset, a computer scientist at the University of Colorado at Boulder, and his collaborators Marina Kogan and Sidney Redner. After analyzing a huge amount of data from basketball, football, and hockey games, they formulated "a simple model in which the score difference randomly moves up or down over time," the New Scientist says. The model is surprisingly accurate, considering that it incorporates no features of the games. It works well for games like basketball, where the scores are fairly large numbers, but is not very reliable for games like soccer, where scores are small. "[S]o you probably shouldn't use it when betting on the English Premier League," the magazine says. Image: Probability that a lead is safe versus the dimensionless lead size for NBA games, showing the prediction from an equation in the paper (eq. 15), the empirical data, and the mean prediction for Bill James's wellknown "safe lead" heuristic, courtesy of Aaron Clauset, Marina Kogan, and Sidney Redner.
See "Winning formula reveals if your team is too far ahead to lose," by Gilead Amit. New Scientist, 11 July 2015 and "Lucky Bounce," by Marcus Woo. Slate, 18 June 2015.
 Allyn Jackson
On a museum's math error that really wasn't, by Claudia Clark
Below we've cited one of several news articles that describe the story of an errorwhich turned out not to be an errorfound by 15yearold Joseph Rosenfeld in the "Mathematica: A World of Numbers...and Beyond" exhibit at the Museum of Science in Boston, Massachusetts. During a visit to the museum on June 4 with his family, Rosenfeld saw that what appeared to be the formula for the Golden Ratio contained a minus sign, and not a plus sign, between the two terms in the numerator. After Rosenfeld left a note to that effect at the front desk of the museum, the museum sent a letter to the Rosenfeld family, agreeing that the minus sign was wrong and that they would correct it, if they could do so without damaging the exhibit. However, once news of this story went viral, others quickly noticed that the exhibit had in fact used the reciprocal of the Golden Ratio, correctly identified as φ in the display. On June 8, the museum released a statement, explaining that "the way the Museum present the Golden Ratio in its exhibit is in fact the less commonbut no less accurateway to present it." Image: The exhibit’s stated value is on the left. It represents the ratio of the short side to the long side in a golden rectangle. Undoubtedly, Rosenfeld was thinking of the value on the right, which is the reciprocal ratio.
See "Math error at Museum of Science? Not so fast." by Cristela Guerra. The Boston Globe, 8 July 2015.
 Claudia Clark
On not being a female role model, by Samantha Faria
Mathematician Eugenia Cheng could be an excellent role model for young women who would like to become mathematicians. She's a successful mathematician who has recently written a book that has received a good deal of attention. But she would rather that role models were unnecessary and people believed that any career is possible, regardless of gender. Cheng grew up in an egalitarian household with both parents working professional jobs. Her dad was often the primary caregiver and prepared the family meals. She attended an allgirls school so gender expectations were never apparent. "Plenty of girls chose math and science. Thinking back now, it's funny to imagine a class full of girls who have chosen physics. But at the time, we thought nothing of it," Cheng explained. The head of her high school tried to dissuade her from studying math in college claiming that the boys would be better prepared than she. Despite the warning, she pursued the subject and excelled. Although Cheng wishes there was no longer a need for "female" role models she understands that "many people need to see women succeeding at things in order to be convinced that it is possible." Photo: RoundTurnerPhotography.com.
See "Why I Don’t Like Being a 'Female Role Model'," by Eugenia Cheng. Bright, 7 July 2015.
Also see previous summary of media coverage of Cheng and her work on Math Digest, On Math and art, by Claudia Clark; "Combining Math and Music" video; "Happy Pi Day" video; and links to reviews of her recent book, How To Bake Pi: An Edible Exploration of the Mathematics of Mathematics.
Samantha Faria
On streamlining and preserving the classification of finite simple groups, by Lisa Dekeukelaere
Group theorists are working to ensure that one of their most important proofsof the Enormous Theoremremains accessible to future generations that are unable to tackle the 15,000 pages the proof currently requires. The Enormous Theorem shows that finite simple group, the building blocks of finite groups, can be partitioned into four categories, and it lists all of the categories. The proof consists of more than 100 journal articles written over decades, and as the mathematicians who first completed it reach their seventies, they are rushing to draft a shorter, "second generation" proof so that their successors will be able to understand and build upon its enormity. The author notes that despite the seeming obscurity of the theorem to the general public, our society has a pattern of scientific advances based on principles proved decades in the past, suggesting opportunities for the Enormous Theorem's future.
See "The Whole Universe Catalog," by Stephen Ornes. Scientific American, July 2015, pages 6875.
 Lisa DeKeukeleare
On beating traffic, by Lisa DeKeukelaere
A traffic model explores the effects of routing strategiesrules for choosing which pathway to follow from Origin to Destination. Roads A and B are long but wide; they allow highspeed travel regardless of traffic. Roads a and b are shorter but also subject to congestion; in heavy traffic, the shortcuts are no faster than the long way around. The dots are cars moving through the network; their colors indicate their route choices. The table of timings at the upper right shows that in this case the shortest route ab is not the fastest. See an interactive version of this illustration. Image: Brian Hayes. 
In 1968, German mathematician Dietrich Braess described a traffic paradox wherein average drive time for getting from point A to point B with two separate route options actually increasedrather than decreasedwith the addition of the option to switch routes halfway if one route became overly crowded. The paradox results from "selfish routing," the assumption that drivers choose the route that will minimize their own travel time, which leads to overcrowding if all of the drivers selfishly choose the same route. Braess's model, however, also unrealistically assumes some roadways have unlimited capacity and infinite speed, and mathematicians more recently have developed similar models with more realistic methods for tracking car movement. The author notes that the applicability of Braess's paradox is changing as more drivers have access to realtime traffic conditions using GPS, and the advent of selfdriving cars could increase the importance of similar traffic modeling. See "Playing in Traffic," by Brian Hayes. American Scientist, JulyAugust 2015, pages 260263.  Lisa DeKeukelaere

Math Digest Archives
 2010  2009 
2008  2007  2006  2005  2004  2003  2002  2001  2000  1999  1998  1997  1996  1995
Click here for a list of links to web pages of publications covered in the Digest. 