Investment and Monetary Policy: Learning and Determinacy of Equilibrium
研究了包含资本的新凯恩斯模型中理性预期均衡的确定性和可学习性，发现通过合理的资本调整成本、产出权重或利率平滑政策，可以实现确定且可学习的均衡。
We explore determinacy and expectational stability (learnability) of rational expectations equilibrium (REE) in New Keynesian (NK) models that include capital. Using a consistent calibration across three different models—labor-only, firm-specific capital, or an economy-wide rental market for capital, we provide a clear picture of when REE is determinate and learnable and when it is not under a variety of monetary policy rules. Our findings make a case for greater optimism concerning the use of such rules in NK models with capital. While Bullard and Mitra's (2002, 2007) findings for the labor-only NK model do not always extend to models with capital, we show that determinate and learnable REE can be achieved in NK models with capital if there is (i) plausible capital adjustment costs, (ii) some weight given to output in the policy rule, and/or (iii) a policy of interest rate smoothing.