Coopetition or co-opetition (sometimes spelled "coopertition" or "co-opertition") is a neologism coined to describe cooperative competition. Coopetition is a portmanteau of cooperation and competition, emphasizing the "petition"-like nature of joint work. Basic principles of co-opetitive structures have been described in game theory, a scientific field that received more attention with the book Theory of Games and Economic Behavior in 1944 and the works of John Forbes Nash on non-cooperative games. Coopetition occurs at inter-organizational or intra-organizational levels.