各位大侠支招啊~
Question 1:
There is a mass of voters who can be lined up over the interval [0; 1].The interpretation is that these voters dier according to their ideological positions. So,0 represents the extreme left whereas 1 the extreme right. Assume the distribution is uniform.There are two political parties, D and R. Assume the only thing the parties care about are winning the election. They choose party platforms, which are two numbers xD [0; 1]and xR [0; 1].
Assume each voter votes for the party whose chosen platform is closest to their own ideological position. So, for example, consider the voter with ideological position rep-resented by the point 0.3. If
xD was 0.2 and xR was 0.45 then this voter will vote for party D since |0.3 - 0.2| < |0.3 - 0.45| If a voter is indi erent then he votes for eitherparty with equal chance.
(i) Set this up as a game. [Mention who are the players, what are their action sets and what are the payoffs.]
(ii) Show one Nash Equilibrium of the game.
(iii) Is the Nash Equilibrium unique? If not, show another than the one you showed in part (ii). If it is unique, then
prove uniqueness.
Question 2:
There are N individuals in a society. Assume N is a positive integer strictly greater than 1. Individual i has income mi > 0. This income can be spent on getting private good ci 0, or contributing to a public good, gi 0. Satisfaction ofbudget constraint requires, as usual, that
ci + gi <=mi By de nition, total public good G is given byG
=n∑i gi Each person's utility function ui(G; ci) is given byu
i(G; ci) = ln(G) + ciwhere remember that \ln" stands for natural logarithm.
(i) Argue rst that budget constraint can be rewritten as
ci + gi = mi. Hence utility function can be rewritten more conveniently as ui(gi; g-i) = ln(G) + mi -gi.(ii) Find a symmetric Nash equilibrium,
bgi and hence the total public good G produced in this Nash equilibrium.(iii) Solve for the socially ecient level of public good
G. (Recall that socially ecient level of public good G is the level of G that maximizes the expression PN i=1 ui(gi; g-i).)(iv) Give the economic rationale behind the fact that
G < G. What happens to theratio
Question 3: Consider the following asymmetric Cournot duopoly. As usual, inversedemand
P(Q) is given by P(Q) = a - Q with Q = q1 + q2 where q1 >0 and q2 >0 arethe outputs of rms 1 and 2 respectively.
The asymmetry is with respect to costs. Assume marginal costs of rms 1 and 2 are
given by
c1 > 0 and c2 > 0 where c1 6= c2. Assume also that there are no xed costs.Solve for the Nash equilibrium (show
all your workings). Consider in particular thefollowing two di
erent scenarios.
(i)
ci < a=2; for both i = 1; 2.(ii) c1 < c2 < a and 2c2 > c1 + a.