A Firefighter's Theorem.(The Talk of the Town)(Bobby Beddia)

One Saturday in August, Rhonda Roland Shearer, the widow of the paleontologist Stephen Jay Gould, was on her way back from the park with her daughter and two grandsons. They made a stop, as they often do, at the fire station on Sixth and Houston, so that the boys could check out the fire trucks. Joey Graffagnino showed the kids around the truck while Shearer chatted with another firefighter, Bobby Beddia. Shearer said recently, "He mentioned that he was very lucky, because he was fifty-three, so this year he got to experience living in his 'birth year.' "

Shearer, an artist who has done some work with fractal geometry and runs a group called Art Science Research Laboratory, asked Beddia what he meant. He explained that he was born in 1953 (in September), so his age matched the last two digits of the year in which he was born: a once-in-a-lifetime occurrence. "He had this glow that I recognized from seeing the faces of mathematicians when they've discovered a beautiful idea," Shearer said. "I told him, 'You should really contact a mathematician to work out a proof.' As I was saying that, I was secretly planning to explore it myself and surprise him."

Shearer and her family went to lunch. A few hours later, she got a call from a friend: a seven-alarm fire had broken out in the vacant Deutsche Bank Building, near Ground Zero, and two firemen--Graffagnino and Beddia--had been killed. Shearer decided to continue investigating Beddia's observation, as a tribute. She called her friend Richard Brandt, a retired N.Y.U. physicist. He pointed out something that would be obvious to mathematicians: the "birth year" can happen only in an even-numbered year--in Beddia's case, the year beginning in 2006, or, in Brandt's case, 1982, the year when he turned forty-one (since he was born in '41). "It's simple, but the originality is to recognize that it's happening," Brandt said the other day.

Shearer told the story to Barry Cipra, a freelance math writer in Minnesota. "When I described it to my wife, she immediately thought of the champagne birthday--when you reach the age of the day of the month you were born," Cipra said. "But nobody I've run this by has ever heard of this notion. What's sort of great about it ...