[The math in this novel which was a best seller in Germany in 2004 is] recognizable not only for experts, so it is mentioned in almost every review. Zeh learned about game theory and the prisoner's dilemma from Robert Axelrod's book "The Evolution of Cooperation", which you might know. She refers explicitly to the theory and uses its models as a blue print for the plot, which is centered around two students, Ada and Alex, who try to lure one of their teachers in a sexual adventure in order to blackmail him. Both want to learn something about the 'game' they set in motion, and they want to figure out whether it is possible to predict human behavior.