Value function iteration

 

We consider the following maximization problem

 

          subject to

 

We introduce technology shock that is a random process. That is

 

 

where

 

 

for

 

We consider the following Bellman equation

 

 

 

We start from E[V0|theta]=0 and k’=0.

 

When j=0

Since  and k’=0

 

 

 

When j=1

That is

Since

FOC w.r.t. k’ is

So

Plugging it into Bellman equation at optimum when j=1

Arranging the first term on the right hand side, we get

In term of k and theta, we can express it as

We can express it as

 

We can repeat this.

 

When j=2

That is

FOC w.r.t. k’ is

So

 

At least we can calculate k’ in the same way and we get

 

   when j=n.

 

That is going to become

 

Thus

 

 

That’s what we got in 0511 by the method of guess and verify. That is not difficult.

 

However, the generalization of value function is a little bit complicated.