We propose a general framework to study the stability of the subspace spanned by P consecutive eigenvectors of a generic symmetric matrix H0 when a small perturbation is added. This problem is relevant in various contexts, including quantum dissipation (H0 is then the Hamiltonian) and financial...

We establish several new stylized facts concerning the intra-day seasonalities of stock dynamics. Beyond the well-known U-shaped pattern of the volatility, we find that the average correlation between stocks increases throughout the day, leading to a smaller relative dispersion between stocks....

Price regulation and competition patterns in the ethical drug industry in france This article gives the results of an econometric modelization of the ethical drugs price and quantity determination institutionnal process for France. From price and promotion elasticities, it is shown that...

Efficiency of financial markets is one of the most studied subjects in theoretical finance. Formalization of this idea is realised by the random walk model. Numerous tests have been developed to validate the hypothesis of identically and independently distributed innovations. But the results of...

Management control practices are influenced by different professional groups, their interpretations and power struggles. We study a company whose strategy and daily management rely on non financial stakes, notably upon the concept of “brand”. We show how management accountants introduce a...

Les nations du sud de la zone Euro ont connu la prospérité dans les années qui ont suivi la création de la monnaie unique. Le bond de la consommation et l’élévation du niveau de vie se sont hélas révélés être des mirages. En favorisant un endettement massif, l’Euro a encouragé un...

When rates of return on bonds are computed over extremely short holding periods, the ex post cross-sectional relationship between realized return and risk is linear. It is therefore possible, at any time, to extrapolate the cross-sectional relationship to a zero risk level, and thus to determine...