Algebraic Independence and Mahler's method

We give some new results on algebraic independence within Mahler's method, including algebraic independence of values at transcendental points. We also give some new measures of algebraic independence for infinite series of numbers. In particular, our results furnishes, for $n\geq 1$ arbitrarily large, new examples of sets (\theta_1,...,\theta_n)\in\mrr^n normal in the sense of definition formulated by Grigory Chudnovsky (1980).Comment: 6 page

Why Has the U.S. Financial Sector Grown so Much? The Role of Corporate Finance.

The share of finance in U.S. GDP has been multiplied by more than three over the postwar period. I argue, using evidence and theory, that corporate finance is a key factor behind this evolution. Inside the finance industry, credit intermediation and corporate finance are more important than globalization, increased trading, or the development of mutual funds for explaining the trend. In the non financial sector, firms with low cash flows account for a growing share of total investment. I build a simple equilibrium model to capture these salient features and I use it to interpret the data. I find that corporate demand is the main contributor to the growth of the finance industry, but also that efficiency gains in finance have been important to limit credit rationing. Overall, the model can account for a bit more than half of the financial sector's growth.

Financiers vs. Engineers: Should the Financial Sector be Taxed or Subsidized?

I study the allocation of human capital in an economy with production externalities, financial constraints and career choices. Agents choose to become entrepreneurs, workers or financiers. Entrepreneurship has positive externalities, but innovators face borrowing constraints and require the services of financiers in order to invest efficiently. When investment and education subsidies are chosen optimally, I find that the financial sector should be taxed in exactly the same way as the non-financial sector. When direct subsidies to investment and scientific education are not feasible, giving a preferred tax treatment to the financial sector can improve welfare by increasing aggregate investment in research and development.

Corporate Governance Over the Business Cycle

I provide empirical evidence that badly governed firms respond more to aggregate shocks than do well governed firms. I build a simple model where managers are prone to over-invest and where shareholders are more willing to tolerate such a behavior in good times. The model successfully explains the average profit differences as well as the cyclical behavior of sales, employment and investment for firms with different governance qualities. The quantitative results suggest that governance conflicts can explain 30% of aggregate volatilitybusiness cycles, corporate governance

Financing Europe's Fast Movers. Bruegel Policy Brief 2008/01, January 2008

Summary. Arguments about structural policies in Europe, including the EU’s Lisbon strategy, put a legitimate emphasis on labour and product market reforms, but often overlook the role of the financial system in fostering innovation and growth. Corporate finance is crucial for the emergence of new companies, well beyond the much-analysed technology sector. In a knowledge economy where companies rely less on physical investment, traditional bank loans are insufficient. While Europe has a world-class financial system for established companies, new instruments tailored to the needs of emerging firms remain underdeveloped in most EU countries

Electrification of the proof mass of a drag-free or accelerometric satellite

The exploitation of the data provided by the Cactus accelerometer, which makes up the payload of the D5B Castor Satellite of CNES confirmed the existence of an electric current charging the proof mass under the influence of the magnetospheric protons, and revealed a periodic variation of this current, due to the passage of the apogee through the South Atlantic magnetic anomaly. Results of in-orbit measurements of this charging current are presented, as well as calculations made for determining this current and its variations from data on proton flux at the satellite altitudes. The comparison of measured and calculated values shows that the calculation method is valid and precise enough to be used for drag-free or accelerometric satellites

Financing Europe's fast movers

This policy brief deals with the link between corporate finance and growth. The discussions about structural reform in Europe, including the EUÂ?s Lisbon strategy, put a legitimate emphasis on labour and product market reforms, but often overlook the role of the financial system in fostering expansion. Thomas Philippon and Nicolas Véron analyse this gap and outline a number of possible policy responses.

Competing on Speed

Two forces have reshaped global securities markets in the last decade: Exchanges operate at much faster speeds and the trading landscape has become more fragmented. In order to analyze the positive and normative implications of these evolutions, we study a framework that captures (i) exchanges' incentives to invest in faster trading technologies and (ii) investors' trading and participation decisions. Our model predicts that regulation that protect prices will lead to fragmentation and faster trading speed. Asset prices decrease when there is intermediation competition and are further depressed by price protection. Endogenizing speed can also change the slope of asset demand curves. On normative side, we find that for a given number of exchanges, faster trading is in general socially desirable. Similarly, for a given trading speed, competition among exchange increases participation and welfare. However, when speed is endogenous, competition between exchanges is not necessarily desirable. In particular, speed can be inefficiently high. Our model sheds light on important features of the experience of European and U.S. markets since the implementation of Reg. NMS, and provides some guidance for optimal regulations.