subgame perfect equilibrium is found using backward induction
subgame perfect equilibrium involves solving each subgame from the final subgames and working up to the first decision
perfect recall involves players remembering past moves and states
common knowledge involves the situation, rules and payoffs being known to all the players
common knowledge and perfect recall are assumed for sequentially played game theory
a sequentially played game can be shown in normal form representation
in a sequentially played game, everyone knows everyone's potential payoffs, and everyone knows everyone knows
each terminal (end) node of a game tree show the payoffs
a branch out of a node of a game tree show the actions available to the player
at each node of a game tree, one player makes a choice
a game tree completely describes the game and situation
a game tree provides a complete description of a sequentially played game
sequentially played games create an extensive form
some Normal form Nash equilibria may be not justifiable, as the actual situation that would cause the outcome will not happen (often because the game has ended)
the Normal form Nash Equilibrium of extensive form games can be used to find a Nash Equilibrium path through the extensive form game tree
the Nash Equilibrium of extensive form games can be found by using the normal form of the game
A strategy profile involves all the best choices in all possible subgames