Posted by Anonymous on Tuesday, November 24, 2009 at 2:14pm.
I don’t get anything from below except for (c). Please help me! Thanks.
Consider the following game matrix:
....................................................Player B............
............................................Left............Right.......
Player A.........Top..............(a, b)...........(c, d).......
.......................Bottom........(e, f)............(g, h).......
a) If (top, left) is a dominant strategy equilibrium, then we know that “a” is greater than ____, “b” is greater than _____, “c” is greater than _______ and “f” is greater than _______.
a > c , b > e , c > f , f > c
b) If (top, left) is a Nash equilibrium, then which of the inequalities from your answer in part (a) must be satisfied?
a > b and b > f
c) If (top, left) is a dominant strategy equilibrium, must it be a Nash equilibrium?
No

MACROeconomics  Game Theory  economyst, Tuesday, November 24, 2009 at 6:50pm
I'm having some trouble with your notation. Let me asssume that (x,y) means that x is the outcome going to player A, y is the outcome going to player B.
If top left is a dominant strategy equilibrium, it implies A perfers outcome Top and B prefers outcome Left. Ergo, I think a>e, b>d, c>g, f>h
Under a Nash equilibrium, a player cannot do better by switching. So if starting in TopLeft, The choice for player A is to move to BottomLeft. If he does not move, it must be that a>e. Similarly, for B not to move, b>d.
We cant say if A would perfer c over g or viceversa. Ditto, we cant tell if B would prefer f over h.
c) I think yes. A dominant strategy equilibrium must also be a Nash equilibrium.