# Category Archives: mathematics

## Divisive factorials!

The other day I was derailed by this tweet from Fermat’s Library: The moment I saw it, I had to stop in my tracks, grab a scratch pad, and check out the formula. The result made sense in a rough-and-ready … Continue reading

## Notes from JMM 2018

The annual Joint Mathematics Meeting always charges my batteries. Here are few items from this year’s gathering in San Diego. A Formal Affair In 1994 a document called the QED Manifesto made the rounds of certain mathematical mailing lists and … Continue reading

## Sir Roger Penrose’s Toilet Paper

Twenty years ago, Kimberly-Clark, the Kleenex company, introduced a line of toilet paper embossed with the kite-and-dart aperiodic tiling discovered by Roger Penrose. When I first heard about this, I thought: How clever. Because the pattern never repeats, the creases … Continue reading

## Approximately Yours

Today, I’m told, is Rational Approximation Day. It’s 22/7 (for those who write dates in little-endian format), which differs from π by about 0.04 percent. (The big-endians among us are welcome to approximate 1/π.) Given the present state of life … Continue reading