latest stories:

## Stories by Evelyn Lamb

For Halloween, I wrote about a very scary topic: higher homotopy groups. Homotopy is an idea in topology, the field of math concerned with properties of shapes that stay the same no matter how you squish or stretch them, as long as you don’t tear them or glue things together.

December 25, 2014 |

• ### Online Game Crowd-Sources Theorems

Now is your chance to prove some theorems without knowing what they mean! Chris Staecker, a mathematician at Fairfield University, created the game Nice Neighbors to get crowd-sourced solutions to problems from a field called digital topology.

December 23, 2014 |

• ### Seeing Music: What Does the Missing Fundamental Look Like?

I wrote a post yesterday about the missing fundamental effect. It’s a startling auditory illusion in which your brain hears a note that is lower than any of the notes that are actually playing.

December 10, 2014 |

Telephones lie about sounds because odd numbers aren't even. Once again with those integers and sound perception! Telephones can only pick up frequencies above 300 or 400 Hertz (cycles per second, also called Hz), but most adults’ speaking voices are lower than 300 Hz (approximately the D above middle C).

December 9, 2014 |

The integers are a unique factorization domain, so we can't tune pianos. That is the saddest thing I know about the integers. I talked to a Girl Scout troop about math earlier this month, and one of our topics was the intersection of math and music.

November 30, 2014 |

• ### The Math Geek Holiday Gift Guide

Looking for a gift that says, "Hey, I know you like math"? Look no further. There is an embarrassment of riches when it comes to wonderful mathematical things to give to people, but here are some of the coolest items I've seen this year.

November 23, 2014 |

• ### A Proof of the Math Fact of Rolle in Short Words

This proof of the math fact of Rolle, I wrote it down; here was my goal: Use just words with one part. (So it won’t sound too smart.) Please tell me if you find a hole.

November 17, 2014 |

• ### Higher Homotopy Groups Are Spooky

When I tell people I'm a mathematician, I get a lot of different reactions. Perhaps surprisingly, I mostly get positive responses. Many of them are of the "You go, girl" variety.

October 31, 2014 |

• ### In Which Omar Khayyam Is Grumpy with Euclid

My math history class is currently studying non-Euclidean geometry, which means we've studied quite a few "proofs" of Euclid's fifth postulate, also known as the parallel postulate.

October 28, 2014 |

• ### Beyond Emmy and Sophie: Resources for Learning about Women in Math

Today is Ada Lovelace Day, an international celebration of women in science, technology, engineering, and math. If you’d like to read about women in math for the occasion, you're in serious danger of coming across an article about Hypatia, Emmy Noether, Sophie Germain, or Sofia Kovalevskaya.

October 14, 2014 |

• ### Build Your Own Fractal with MegaMenger!

Later this month, people will be gathering at museums and schools around the world to build giant Menger sponges as part of a global fractal extravaganza called MegaMenger.

October 9, 2014 |

• ### Another Reason to Love the Number Seven

The world's favorite number is seven, at least if the result of a poll conducted by Alex Bellos is to be believed. Some people like it because it is prime, some because they have a lot of sevens in their birthdates.

September 29, 2014 |

• ### Extrapolation Gone Wrong: the Case of the Fermat Primes

Samuel Arbesman recently wrote about incorrect mathematical conjectures. I wanted to add one of my favorites, which came up in my math history class a couple weeks ago.

September 26, 2014 |

• ### A Computer Scientist Tells Mathematicians How To Write Proofs

Believe it or not, I do have friends who would describe themselves as not liking math, and every so often one of them will share this meme on Facebook: And then Satan said, "Put the alphabet in math." There are different background pictures each time the meme pops up, but the text is always the [...]

September 24, 2014 |

• ### Mathematics, Live: A Conversation with Evelyn Boyd Granville

Evelyn Boyd Granville was one of the first African American women to earn a Ph.D. in mathematics. She recently turned 90, and I wrote a post here to celebrate.

September 5, 2014 |

• ### Ancient Babylonian Number System Had No Zero

As I told my class on Thursday, the theme of the first week of our math history course was "easy algebra is hard in base 60." We started the semester in ancient Mesopotamia, trying to understand Babylonian* mathematical notation and decipher Plimpton 322, an enigmatic tablet from about 1800 BCE.

August 31, 2014 |

• ### In Praise of Proofs by Contradiction that Aren't

If you don't know what to do, do something. That's one of my mottos when I teach math (and it's probably good life advice too). Last year, I taught introductory analysis (basically calculus with the juicy bits left in), one of the first proof-oriented classes students take.

August 28, 2014 |

• ### What Is the Goal of a Math History Class?

I'll be teaching a math history class for the first time this semester. I'm excited to be teaching it, but I've noticed that preparing for this class has been very different from preparing for other classes I've taught, which have all been math content courses.

August 22, 2014 |

• ### How to Talk About the Fields Medal at Your Next Cocktail Party

On Wednesday, four mathematicians will receive the prestigious Fields Medal at the International Congress of Mathematicians (ICM) in Seoul.

August 11, 2014 |

• ### Math Twitter Bots, Reviewed and Rated

In the course of being a math person on Twitter, I have run across some math-related Twitter bots and feeds. It would just be mean to grade my human tweeps, but I have no qualms about rating the bots!

July 28, 2014 |

• ### The Shocking Failure of British Rail Travel to Respect the Triangle Inequality

I spent about a month in the UK earlier this summer, and that meant I took a lot of train trips. I love riding trains: the feeling of endless possibility I get when I look at the departure boards, the countryside rolling by, the fantastic people-watching, the two-hour delay between Edinburgh and Manchester because a [...]

July 23, 2014 |

• ### Some Infinities Are Bigger than Other Infinities, and Some Are Just the Same Size

Warning: contains minor spoilers for The Fault in Our Stars. I recently read The Fault in Our Stars by John Green, now a major motion picture that has led to theft in Amsterdam and a shortage of dry eyes in movie theaters around the world.

July 10, 2014 |

• ### British Objects of Constant Width

As I wrap up a trip to the UK, I reflect on the many objects of constant width I encountered here. I’ll let Numberphile tell you a little more about objects of constant width.

July 4, 2014 |

• ### Really Big Numbers (Book Review)

"Now and then we pluck numbers from the blur...numbers which have no names except the ones we might now give them...souvenirs from alien, unknowable worlds." -Really Big Numbers by Richard Evan Schwartz Really Big Numbers by Richard Schwartz, a mathematician at Brown University, is the first children’s book published by the American Mathematical Society.

June 30, 2014 |

• ### The Most Mathematically Perfect Day of the Year

Whether you write it 6/28 or 28/6, today is a perfect day. A perfect number is a number that is the sum of its factors besides itself, and 6 (1+2+3) and 28 (1+2+4+7+14) are the first two perfect numbers.

June 28, 2014 |