Computer geometry: Rep-tiles with a hole

A cube is an 8-rep-tile: it is the union of eight smaller copies of itself. Is there a set with a hole which has this property? The computer found an interesting and complicated solution, which then could be simplified. We discuss some problems of computer-assisted research in geometry

Differentiability of fractal curves

While self-similar sets have no tangents at any single point, self-affine curves can be smooth. We consider plane self-affine curves without double points and with two pieces. There is an open subset of parameter space for which the curve is differentiable at all points except for a countable set. For a parameter set of codimension one, the curve is continuously differentiable. However, there are no twice differentiable self-affine curves in the plane, except for parabolic arcs

Is there Evidence of Shift-Contagion in International Housing Markets?

The paper attempts to provide, for housing markets, evidence of "shift-contagion" at the international level, i. e. regime shifts in the transmission of asset prices during crisis periods. The focus is in particular on UK and Spain. We use a Markov Switching FAVAR framework and regime-dependent impulse response functions. The `Crisis' regime which we identify endogenously is shown to also correspond to an exogenously determined index of frequency of financial crises in OECD countries, which peaked in the early 1990s and in the more recent Subprime crisis. Furthermore, we find that the response of domestic house price to a shock to a common (global) house price factor during a `Crisis' regime is relatively more amplified than in a `Normal' (more tranquil) regime. Less compelling evidence is found for France.contagion, housing market, regime shifts, FAVAR model

Assessment of “stress tests” conducted on the French banking system.

During the first quarter of 2004, the General Secretariat of the Commission bancaire (SGCB) and the Directorate General Economics and International Relations (DGEI) of the Banque de France conducted an assessment of the stability of the French banking system and its capacity to withstand a set of macroeconomic and financial shocks, as part of a broader evaluation of the French financial system carried out under the auspices of the IMF’s Financial Sector Assessment Program (FSAP). The assessment employed a macro-prudential approach which seeks to quantify the effects of shocks to the banking system using “stress tests”. The tests measured the impact of severe shocks, deemed plausible but infrequent: e.g., a recession, a large movement in interest rates, an oil price shock, a sharp drop in stock prices. This report discusses in detail the principal characteristics of the “stress tests” and the innovations introduced during the French FSAP, including in particular the design of coherent scenarios, which were developed using the DGEI’s macroeconomic model and the SGCB’s financial models for measuring risk. The results of the assessment indicate that, given the high average solvency ratio, the French banking system is currently in a position to withstand a major macroeconomic shock, such as a prolonged recession lasting two years. This type of shock would, however, erode the quality of bank assets and reduce bank profits by 38.5% in the second year, compared with the baseline, resulting in a decline in the international solvency ratio of one percentage point (using the Basel I methodology) or two percentage points (using the new methodology proposed in the Basel II Accord). Other scenarios, such as a 32% depreciation of the dollar against the euro for two years or an increase of nearly 50% in the price of oil also for two years, would have more limited effects on net income and solvency ratios.

Systemic risk: A survey

This paper develops a broad concept of systemic risk, the basic economic concept for the understanding of financial crises. It is claimed that any such concept must integrate systemic events in banking and financial markets as well as in the related payment and settlement systems. At the heart of systemic risk are contagion effects, various forms of external effects. The concept also includes simultaneous financial instabilities following aggregate shocks. The quantitative literature on systemic risk, which was evolving swiftly in the last couple of years, is surveyed in the light of this concept. Various rigorous models of bank and payment system contagion have now been developed, although a general theoretical paradigm is still missing. Direct econometric tests of bank contagion effects seem to be mainly limited to the United States. Empirical studies of systemic risk in foreign exchange and security settlement systems appear to be non-existent. Moreover, the literature surveyed reflects the general difficulty to develop empirical tests that can make a clear distinction between contagion in the proper sense and joint crises caused by common shocks, rational revisions of depositor or investor expectations when information is asymmetric ('information-based' contagion) and 'pure' contagion as well as between 'efficient' and 'inefficient' systemic events. JEL Classification: G21, G29, G12, E49banking crises, Contagion, currency crises, financial markets, financial stability, payment and settlement systems, systemic risk

Fiscal Policy in the Transition to Monetary Union: a Structural VAR Model

In order to assess the effect of fiscal rules in Stage Three of EMU for France and Germany, Bayoumi and Eichengreen's (1992) structural VAR analysis is extended by including the general government financial surplus and conditioning by external variables. This allows a distinction between fiscal and monetary shocks. During the period 1972.1-1995.4, monetary policy has a significant effect on prices in both countries. On the other hand, fiscal shocks, whose effect on the deficit provides a measure of the " structural deficit ", only contribute to a significant part of the dynamics of output in Germany. For that period, they appear to have little effect in France. In addition, fiscal shocks are uncorrelated between the two countries, although it is difficult to conclude that it reflects purely idiosyncratic shocks rather than a different policy-mix.Budget deficit ; Ricardian equivalence ; Structural VAR ; EMU