This book studies the sustainability and optimality of public debt under different scenarios: the closed economy, the small open economy, and a two-country setting. Sustainability refers to the existence and the stability of the long-run equilibrium. Optimality relates to the path of public debt that maximizes discounted utility. The analysis is conducted within the framework of the Solow model, the overlapping generations model and the infinite horizon model. The government can follow different strategies, it either fixes the deficit ratio or the tax rate. As a result, a fixed deficit ratio generally can be sustained. By contrast, a fixed tax rate generally cannot be sustained. Depending on the chosen fiscal strategy, there exists either an optimal deficit ratio or an optimal tax rate that maximizes the sum of consumption and government purchases per capita.
This book studies the dynamics of monetary and fiscal interactions in the Euro Area. The policy makers are the European Central Bank and national governments. The primary target of the ECB is low inflation. And the primary target of a national government is low unemployment. However, there is a short-run trade-off between low inflation and low unemployment. Here the main focus is on sequential policy decisions. Another focus is on simultaneous and independent policy decisions. And a third focus is on policy cooperation. There are demand shocks, supply shocks, and mixed shocks. There are country-specific shocks and common shocks. The key question is: Given a shock, what are the dynamic characteristics of the resulting process?