Handouts

Strategic Interdipendence & Game Theory Basics:

Table Of Contents

-> Market Structure is the more determinant thing that define the performance of a firm.

-> Number of firms in an industry:

  • OLIGOPOLY: from greek oligos: few, polein: sell

-> Ex: airlines in US, Smartphones industry

  • STRATEGIC INTERDEPENDENCE: is the idea that the strategy of a firm must take into account the strategy of all the other firms.

Tools:

-> PROFIT MAXIMIZATOIN RULE: neoclassical profit maximizatoin logic.

-> GAME THEORETICAL INSIGHTS: strategic interdependence.

Game Theory:

-> DEF: formal modeling of optimal decision-making in contexts of strategic interaction.

-> RULES Simplest version (simultaneous game, two players, pure strategies):

2 players Each player has a set of possible actions (discrete or continuous) Different combinations of actions unambiguously determine different outcomesEach outcome is unambiguously associated to a pay-off for reach each player Players are perfectly rational and perfectly informed Players decide their actions simultaneously (🎯 pay-off maximization)

-> KEY CONCEPTS:

  • REACTION FUNCTION: function associating each possible strategy of one player with the optimal response of the other player
  • NASH EQUILIBRIUM: configuratoin of strategies where each player’s strategy is the best response to the strategy of the other player. A configuration of strategies is a Nash equilibrium if no player could improve the resulting pay-off by unilaterally deviating from the selected strategy.

-> EXAMPLE:

Payoff is in USD in millions 
100, 60 
150, 20 
Cut Advertising 
80, 100 
Cut Advertisi ng 
No Change 
Increase Advertisi ng 
Firm B 
No Change 
-10, 90 
o, 20 
130, 50 
Increase Advertising 
-50, 80 
30, 50 
50, 20 A cut B cut 
A no change B cut 
A increase B no change 
B cut A increase 
B no change -->A increase 
B increase A increase 
A increase B no change is the only Nash equilibrium “></td></tr></tbody></table></figure>



<h3 class=Sequential Games:

-> RULES:

  • There are 2 players
  • Each player has a set of possible actions, which may be discrete or continuous.
  • Different combinations of actions unambiguously  determine different outcomes.
  • Each outcome is unambiguously associated to a pay-off for each player.
  • Players are perfectly rational and perfectly informed.
  • Players decide their actions sequentially, aiming for pay-off maximization.

The player acting first is known as the leader, while the other is known as the follower.

Solving:

-> Reperesented as Decision Trees

-> SOLVED backward induction: start by determining the pay-off maximizing strategy of the follower

  • Subgame Perfect Nash Equilibrium: The sequence of optimal actions obtained through backward induction.

Lascia un commento

Il tuo indirizzo email non sarà pubblicato. I campi obbligatori sono contrassegnati *

Torna in alto