# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Prisoners of the Dilemma," by Martin A. Nowak. *Nature*, 5 February 2004.

Nowak describes how mathematician Karl Sigmund introduced him to "the prisoner's dilemma," a game in which two players have a choice between cooperation and defection. The author describes how complicated and interesting the game can become. He introduces the concept of tit-for-tat (TFT) in a single game and in round robins and discusses how researchers in many disciplines have been interested in the prisoner's dilemma. Nowak was a first-year Ph.D. student in biochemistry when he met Sigmund on a holiday, "the turning point that brought together mathematics and biology." He confesses he's "no longer embarrassed to work on games" and is now at the Program for Evolutionary Dynamics at harvard University.

*--- Annette Emerson*