# Just in Time for Pi Day...

According to David H. Bailey and Jonathan Borwein, the number pi stands apart. Unique among mathematical constants, it captures the fascination of both professional mathematicians and the public. Pi is also, they argue, the only mathematical topic from antiquity still being researched today.

Writing in the March issue of the *American Mathematical Monthly*, Bailey (Lawrence Berkeley National Laboratory) and Borwein (Centre for Computer Assisted Research Mathematics and its Applications, University of Newcastle) recap the history of pi and describe recent research on whether pi is normal, that is, whether its digits are statistically random in a specific sense.

Titled “Pi Day is upon us again and we still do not know if Pi is normal,” the pair’s paper is available now from the Mathematical Association of America’s website.

Before they get into the math—before they explain the Salamin-Brent algorithm or discuss the benefits of displaying the digits of pi graphically as a random walk—Bailey and Borwein list a sampling of pi’s plentiful appearances in popular culture. There are piems (phrases or verse whose letter count, ignoring punctuation, gives the digits of pi), a *New York Times* puzzle prominently featuring the constant, and numerous television and movie cameos.

When, for instance, a 1993 episode of *The Simpsons* had Apu proclaiming the 40,000th digit of pi to be 1, it was Bailey who furnished the screenwriters with that fact.

The paper’s primary contribution to the literature, though, isn’t its catalog of pi sightings, or even the run-down of advances in pi-related research that follows. The take-home, says Bailey, is the argument that “modern computing technology has fundamentally changed the game for the analysis of pi and other well-known mathematical constants.”

In the paper’s conclusion, the authors note that while many basic questions about pi remain unanswered, “the advent of the computer might at last give humankind the power to answer some of them.”

Want to be prepared to appreciate these imminent advances? Get up to speed with “Pi Day is upon us again and we still do not know if Pi is normal.” *Monthly* editor Scott Chapman says it’s sure to be a hit.

**About The American Mathematical Monthly:**

*The American Mathematical Monthly*publishes articles, notes, and other features about mathematics and the profession. Its readers span a broad spectrum of mathematical interests and abilities. The MAA publishes 10 issues of the

*Monthly*per year.

**About MAA:** The Mathematical Association of America is the largest professional society that focuses on mathematics accessible at the undergraduate level. Formed in 1915, the association members include university, college, and high school teachers; graduate and undergraduate students; pure and applied mathematicians; computer scientists; statisticians; and many others in academia, government, business, and industry who are interested in the mathematical sciences.

**About Lawrence Berkeley National Laboratory:** Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.