Game Theory Practice Sheet
Question 1
Consider the following normal form game:
(a) Write down the strategy form game.
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed stategy Nash equilibrium?
Question 2
Consider the following normal form game:
|
L |
M |
R |
U |
1,1 |
0,0 |
0,3 |
D |
0,0 |
2,2 |
3,0 |
(a) Write down the strategy form game.
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed stategy Nash equilibrium?
Question 3
Consider a Stackelberg game with two firms with identical constant marginal cost c > 0. Firm 1 is the leader and observes its marginal cost and chooses its output quantity first. Then, firm 2, the follower, observes the output choice of firm 1 and chooses its output quantity.
(a) Write down the payoff function of each firm.
(b) Find the Stackelberg equilibrium.
Question 4
Consider a Cournot game with quantity-setting firms. There are two firms in the market and they have constant and identical marginal cost c > 0. Their demand function is p = a − bQ, where Q is the total amount of output and a, b > 0.
(a) Write down the profit function of each firm.
(b) Find the Nash equilibrium.
Question 5
Players A and B play a game. Each chooses left (L) or right (R). If both players choose L, player A gets 2 units and player B gets 1 unit. If both players choose R, player A gets 1 unit and player B gets 2 units. If the players choose differently, both get 0. The players choose simultaneously and independently.
(a) Construct the normal form of the game.
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed strategy Nash equilibrium?
Question 6
Consider the following game where two players play rock-paper-scissors by choosing rock (R), paper (P), or scissors (S):
|
R |
P |
S |
R |
0,0 |
0,1 |
1,0 |
P |
1,0 |
0,0 |
0,1 |
S |
0,1 |
1,0 |
0,0 |
(a) Construct the normal form of the game.
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed strategy Nash equilibrium?
Question 7
Consider a coordination game with two players where the payoff function is as follows:
(a) Are there any dominant strategies?
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed strategy Nash equilibrium?
Question 8
Consider a prisoner's dilemma game. Two players, A and B, have the following payoff matrix:
(a) Is there any dominant strategy for either player?
(b) Find all pure strategy Nash equilibria.
(c) Can you find a mixed strategy Nash equilibrium?
Question 9
Consider a Hotelling's game with two firms selling a homogeneous product that is located at the endpoints of a line of length 1. Each consumer is located uniformly at random on the unit interval and has transportation cost t > 0 per unit distance. If two firms locate at x and y, respectively, then consumers choose the closest store.
(a) Write down the profit function of each firm.
(b) Find the location of the firms in the Nash equilibrium.
Question 10
Consider a war of attrition game between two players. The value of the contest for each player is H/2 where H is the common value of the prize. The players choose to quit the contest at some random time. The player who quits first wins nothing, and the other player wins the prize minus the total elapsed time.
(a) Write down the payoff function of each player.
(b) Find the symmetric Nash equilibrium.