Definition: Let $(N, A, u)$ be normal-form game, and for any set $X$ let $\Pi(X)$ be the set of all probability distributions over $X$. Then the set of fixed strategies for player $S_i=\Pi(A_i)$. ...
I'm trying to study game theory myself but i can't found resources with a formal treating of the theme and from this arise my next questions: what is the formal definition of a game in game theory? ...