N'afọ 1965, Reinhard Selten webatara echiche ngwọta ya nke subgame zuru oke equilibria, nke mere ka ọ dịkwuo mma nke Nash equilibrium (mgbe e mesịrị ọ ga-ewebata izu oke aka na-ama jijiji). Na 1994 Nash, Selten na Harsanyi ghọrọ Economics Nobel Laureates maka onyinye ha na usoro egwuregwu akụ na ụba. Ajụjụ: Kedu echiche akụ na ụba nyeere aka imeziwanye Nash equilibrium?
subgame zuru oke equilibria