第14章　产品市场和货币市场的一般均衡.pptVIP

When Keynes’s General Theory was published in 1936, there were many debates about what Keynes really meant. In 1937, Hicks summarized what he saw as one of Keynes’s main contributions: the joint description of goods and financial markets. His analysis was later extended by Hansen. Hicks and Hansen called their formalization the IS-LM model. IS-LM模型的分析框架 §14.2 IS曲线 Two sector three sector IS curve:algebra Y=C(Y-T)+I(r)+G, C=a+b(Y-T), I=e-dr 三、Fiscal policy IS curve 五、其他货币需求理论 货币需求的存货理论（鲍谟和托宾的现金管理模型） 鲍谟和托宾发现人们持有现金的平均数量与去银行提取现金的频率有关。 假如一个人一年需要花费Y元，如果他只去一次银行，则他在年初持有从银行一次性提出的Y元，平均持有现金量为Y/2 如果这个人一年去两次银行，则他在年初时持有现金量为Y/2，持有现金的平均数量为Y/4。 如果这个人一年之中去银行N次，则每次只需提出Y/N元，持有现金的平均数量就是Y/2N元。 去银行次数N的决定 现金管理两种成本：一种是所放弃的银行利息r，等于rY/2N；另一种是往返银行所花费的时间及麻烦(称为交易成本)。假设每次往返银行的各种麻烦及所费时间相当于F元的损失，且这一损失是常数，则交易成本等于FN。总成本C相当于利息损失和交易成本之和： 求导便可求得最优的去银行次数N*： 因此，最优的持有现金的平均量则为： the demand for money Keynes : liquidity money approach transaction motive prudence motive speculation motive Money demand function Money demand curve Money demand function: MD/p=L(r, Y)=L1(r)+L2(y) An individual’s money demand depends on two variables, his level of transactions, and the interest rate. Thus, money demand for the economy as a whole depends on the overall level of transactions in the economy and on the interest rate. The overall level of transactions in the economy is hard to measure. But it is reasonable to assume that it is roughly proportional to nominal income. Monetary policy : open market operations If the central bank wants to increase the amount of currency in the economy, it buys bonds and pays for them by printing money. If it wants to decrease the amount of money, it sells bonds, and removes from circulation the money it receives in exchange for the bonds. So called because they take place in the “open market” for bonds. the determination of the interest rate Equilibrium in financial markets requires that money supply be equal