The Cournot model.
wNash equilibrium:
John F. Nash, Jr (1928-)
Antoine Augustin Cournot (1801-1877)
“A set of strategies is called a Nash equilibrium if, holding the strategies of all other firms constant, no firm can obtain a higher payoff (profit) by choosing a different strategy.  Thus, in a Nash equilibrium, no firm wants to change its strategy.” (Carlton & Perloff, p. 157.)
wCournot model.
wFirms compete by choosing quantity.
wFirms can’t coordinate or commit.
wFirms calculate optimal response to all possible moves by opponents.
wCournot-Nash equilibrium.