Nashova ravnoteža.

One of the most important and probably the most popular concepts of game theory is Nash equilibrium. In this paper we wish to explain the notion of Nash equilibrium in presence of pure and mixed strategies in simple and understandable way. With numerous examples we will motivate and introduce some basic game theory notions. We will illustrate the difference between perfect rationality of a player and the common knowledge of rationality of all players, and how to use that knowledge in order to win the game. In order to demonstrate that we have performed the popular "Guess 2/3 of the average" game in several high-schools in the city of Osijek. [ABSTRACT FROM AUTHOR]