Constructive Fractional-Moment Criteria for Localization in Random Operators

We present a family of finite-volume criteria which cover the regime of exponential decay for the fractional moments of Green functions of operators with random potentials. Such decay is a technically convenient characterization of localization for it is known to imply spectral localization, absence of level repulsion, dynamical localization and a related condition which plays a significant role in the quantization of the Hall conductance in two-dimensional Fermi gases. The constructive criteria also preclude fast power-law decay of the Green functions at mobility edges.Comment: Announcement and summary of results whose proofs are given elsewhere. LaTex (10 pages), uses Elsevier "elsart" files (attached

Wage Flexibility and Openness

This paper analyzes the degree of short-run, real wage flexibility in a two-sector economy under floating rates. This is done by deriving optimal wage indexation in a contracting framework. We find that the more closed the economy, the lower the degree of wage indexation. As a result, output will fluctuate less around its desired level in a more closed economy. These findings further imply that a given unexpected monetary shock will cause as maller output shock in a more open economy, whereas a given real shock will induce a smaller output shock in a more closed economy.

Capital Controls and Financial Crises

The purpose of this paper is to explain the reluctance of developing countries to open up their capital market to foreigners, and the conditions inducing an emerging market economy to switch its policies. We consider an economy characterized initially by a one-sided openness to the capital market domestic agents can borrow internationally, but foreign agents cannot hold domestic equity. We identify conditions under which the emerging market's capitalists would oppose financial reform. This would be the case if 'green field' investment by multinationals would bid up real wages, reducing thereby the rents of domestic capitalists. A financial crisis that raises the domestic interest rate and causes a real exchange rate depreciation may induce the emerging market's capitalists to support opening up the economy to FDI. This attitude switch is more likely to occur the greater the debt overhang, the lower the borrowing constraint, and the weaker the market power of foreign entrepreneurs. Even in these circumstances, the emerging market's capitalists would prefer a partial reform to a comprehensive one -- they would prefer to maintain the restrictions on 'green field' FDI.

Optimal Wage Re-Negotiation

This paper investigates an economy in which there are short-term wage contracts that are re-negotiated under certain conditions. This paper determines the optimal frequency of wage re-negotiation and shows that it depends positively on measures of aggregate variability and Phillips curve slope. The role of optimal wage re-negotiation is to mitigate the output effects of various shocks. In the context of an open economy, it is shown that the desirable exchange rate regime in an economy with optimal wage re-negotiation depends on the stochastic structure of the economy.

Optimal Buffer Stocks and Precautionary Savings with Disappointment Aversion

Developing countries use various risk reduction schemes, ranging from active management of buffer stocks and international reserves to commodity stabilization funds. The purpose of this paper is to reexamine the design of these schemes in a generalized expected utility maximization model where agents are disappointment averse. We derive first the generalized risk premium, showing that disappointment aversion increases the conventional risk premium by a term proportional to the standard deviation times the degree of disappointment aversion. Next, we show that disappointment aversion modifies the characteristics of precautionary saving. The concavity of the marginal utility continues to determine precautionary saving, but its effect is of a second order magnitude (proportional to the variance) compared to the first order effect (proportional to the standard deviation) induced by disappointment aversion. Hence, higher volatility increases the precautionary saving of a disappointment averse agent. This result applies even if the income process approaches a random walk. Finally, we reexamine the optimal size of buffer stocks, showing that disappointment aversion increases its size by a first order magnitude. A buffer stock that is rather small when agents are maximizing the conventional expected utility is rather large when agents are disappointment averse.

International Reserves Management and the Current Account

The paper assesses the costs and benefits of active international reserve management (IRM), shedding light on the question of how intense should IRM be for an emerging market. In principle, an active IRM strategy could lower real exchange rate volatility induced by terms of trade shocks; provide self insurance against sudden stops; reduce the speed of adjustment of the current account; and even allow for higher growth if it fosters exports (“mercantilist” motive). The message of the report is mixed – management of reserves is not a panacea. The mercantilist case for hoarding international reserves, as an ingredient of an export led growth strategy, is dubious. Done properly, IRM augments macro economic management in turbulent times, mitigating the impact of external adverse shocks and allowing for a smoother current account adjustment. These benefits are especially important for commodity exporting countries, and countries with limited financial development.

Lebowitz Inequalities for Ashkin-Teller Systems

We consider the Ashkin-Teller model with negative four-spin coupling but still in the region where the ground state is ferromagnetic. We establish the standard Lebowitz inequality as well as the extension that is necessary to prove a divergent susceptibility.Comment: Ams-TeX, 12 pages; two references added, final version accepted for publication in Physica

Tariff Liberalization Policy and Financial Restrictions

The purpose of this paper is to assess how restrictions on capital mobility affect adjustment to a tariff liberalization policy. This is done by comparing the adlustment process under free and restricted convertibility of foreign assets in a regime where the commercial exchange rate is pegged. It is shown that trade liberalization causes in the short run a larger drop in domestic goods prices and a smaller current account deficit in a regime with restricted convertibility. Similar results apply also for the long-run current account effects of the liberalization: they are smaller under financial restrictions.

Trilemma and Financial Stability Configurations in Asia

This paper takes stock of recent research dealing with the degree to which the trilemma choices of Asian countries facilitated a smoother adjustment during the global crisis of 2008–2009, and the way the region has been coping with the adjustment to the postcrisis challenges. We point out that emerging Asia has converged to a middle ground of the trilemma configuration: limited financial integration, a degree of monetary independence, and controlled exchange rate buffered by sizable international reserves.trilemma choices; financial stability; global crisis 2008–2009