The economic model is that your utility function (over world histories) is the integral over all time of a quantity that depends only on the instantaneous state of the world times a quantity that depends only on the time index. Typically this latter quantity is of the form e^(-kt), and k is called the discount rate.
The economic model is that your utility function (over world histories) is the integral over all time of a quantity that depends only on the instantaneous state of the world times a quantity that depends only on the time index. Typically this latter quantity is of the form e^(-kt), and k is called the discount rate.