Tài liệu tham khảo Tài liệu trung cấp môn Kinh tế vi mô bằng tiếng Anh gồm 41 phần giúp sinh viên khoa kinh tế học tốt môn Kinh tế vi mô. Tài liệu này là phần 11 giới thiệu về " Intertemporal " | CHAPTER 1 0 INTERTEMPORAL CHOICE In this chapter we continue our examination of consumer behavior by considering the choices involved in saving and consuming over time. Choices of consumption over time are known as intertemporal choices. The Budget Constraint Let us imagine a consumer who chooses how much of some good to consume in each of two time periods. We will usually want to think of this good as being a composite good as described in Chapter 2 but you can think of it as being a specific commodity if you wish. We denote the amount of consumption in each period by ci C2 and suppose that the prices of consumption in each period are constant at 1. The amount of money the consumer will have in each period is denoted by m n . Suppose initially that the only way the consumer has of transferring money from period 1 to period 2 is by saving it without earning interest. Furthermore let us assume for the moment that he has no possibility of THE BUDGET CONSTRAINT 183 constraint when the Figure borrowing money so that the most he can spend in period 1 is mi. His budget constraint will then look like the one depicted in Figure . We see that there will be two possible kinds of choices. The consumer could choose to consume at mi m2 which means that he just consumes his income each period or he can choose to consume less than his income during the first period. In this latter case the consumer is saving some of his first-period consumption for a later date. Now let us allow the consumer to borrow and lend money at some interest rate r. Keeping the prices of consumption in each period at 1 for convenience let us derive the budget constraint. Suppose first that the consumer decides to be a saver so his first period consumption ci is less than his first-period income mi- In this case he will earn interest on the amount he saves mi Ci at the interest rate r. The amount that he can consume next period is given by c2 m2 mi - ci r mi - cj m2 1 T r mi - cx . This
