A note on quality choice with an extended Mussa and Rosen's model

We suggest a model derived from the well-known Mussa and Rosen's model, in which two populations of consumers of opposite tastes co-exist: they rank in exactly the reverse order variants sold at the same price. This model may account for linked and contradictory characteristics in products (as for instance nutritional quality and taste), with consumers attaching more importance to one or to the other aspect. The subgame perfect equilibrium is fully characterized for a costless duopoly choosing qualities then prices.opposite tastes.

Existence of Conformal Metrics on Spheres with Prescribed Paneitz Curvature

In this paper we study the problem of prescribing a fourth order conformal invariant (the Paneitz curvature) on the $n$-sphere, with $n\geq 5$. Using tools from the theory of critical points at infinity, we provide some topological conditions on the level sets of a given positive function under which we prove the existene of a metric, conformally equivalent to the standard metric, with prescribed Paneitz curvature.Comment: 20 page

Predicting financial markets with Google Trends and not so random keywords

We check the claims that data from Google Trends contain enough data to predict future financial index returns. We first discuss the many subtle (and less subtle) biases that may affect the backtest of a trading strategy, particularly when based on such data. Expectedly, the choice of keywords is crucial: by using an industry-grade backtesting system, we verify that random finance-related keywords do not to contain more exploitable predictive information than random keywords related to illnesses, classic cars and arcade games. We however show that other keywords applied on suitable assets yield robustly profitable strategies, thereby confirming the intuition of Preis et al. (2013)Comment: 8 pages, 4 figures. First names and last names swappe

The Paneitz Curvature Problem on Lower Dimensional Spheres

In this paper we prescribe a fourth order conformal invariant 9the Paneitz Curvature) on five and six spheres. Using dynamical and topological methods involving the study of critical points at infinity of the associated variational problem, we prove some existence results.Comment: 34 page