Magazine Highlights a Firefighter's Theorem

November 20, 2007

A recent issue of the New Yorker magazine featured a short article about a new mathematical theorem named in honor of New York firefighter Bobby Beddia.

In 2006, when he turned 53, Beddia had observed that he was experiencing his "birth year" — the once-in-a-lifetime occurrence when his age matched the last two digits of the year in which he was born. Sadly, Beddia died the same year in a major fire.

Mathematician-author Barry Cipra later heard about Beddia's observation from Rhonda Roland Shearer, who had happened to meet Beddia. Cipra thought about Beddia's notion and ended up writing a short paper on the subject.

"It struck me," Cipra told the New Yorker, "that, at any given moment, the world consists of two types of people: those who have reached their 'Beddian' age, and those who haven't."

The situation boiled down to the mathematical question: "What is the range of ages of people who are pre-Beddian?" Cipra needed several days to come up with an answer. He dubbed the result the "Beddia Theorem."

It goes like this. "In any odd-numbered year, there are exactly 50 pre-Beddian ages. In any even-numbered year, there are exactly 49 pre-Beddian ages. Moreover, with three exceptions, these ages consist of two separate spans. The exceptions are 1998 (or any year ending in '98), for which the pre-Beddian ages comprise the single span 0-48, 1999 (or any year ending in '99), for which they comprise the single span 0-49, and 2000 (or any year ending in '00), for which they comprise the single span 1-49."

Source: New Yorker, Nov. 12, 2007.