Casual empiricism suggests higher quality is associated with greater variety. However, recent theoretical and empirical research has either not considered this link, or has been unable to establish unambiguous predictions about the relationship between quality and variety. In this paper we...

In their recent paper Derigs and Marzban (2009) argued that Sharia’a-compliant strategies result in much lower portfolio performance than the conventional strategies. The main reason for their argument is of Sharia’a-compliance limits on the set of admissible investments. However, in the...

Casual empiricism suggests higher quality is associated with greater variety. However, recent theoretical and empirical research has either not considered this link, or has been unable to establish unambiguous predictions about the relationship between quality and variety. In this paper we...

In this paper I described group theoretic methods that can be used for analyzing the boundary problems, which arise when the Hamiltonian method is applied to solve the relaxed problem for the multidimensional screening problem. This technique can provide some useful insights into the structure...

In this paper I consider a monopolistic screening model with continuum of types when the type set is a disconnected subset of the real line. I prove that the product line remains connected provided that the gap in the type space is sufficiently small. I also use the results to show that the...

In this paper I consider a model of coexisting moral hazard and adverse selection, similar to one considered by Guesnerie, Picard, and Rey (1989). I provide an explicit solution for the optimal incentive scheme in the case, when the effort is observed with a normally distributed error. The main...

We consider a general agency model with coexisting hidden action and hidden information. We prove that, with minor technical qualifications, independence of the production technology from the consumer type is necessary and sufficient for welfare irrelevance of hidden action. Our result clarifies...

In this paper I revisit the Mussa and Rosen (1978) model. However, unlike Mussa and Rosen, I assume that there is a positive mass of the consumers of the highest possible type. I call them snobs. I prove that snobs consumers are served efficiently and the product line decreases in the mass of...

In this paper I describe group theoretic methods that can be used for analyzing the boundary problems, which arise when the Hamiltonian method is applied to solve the relaxed problem for the multidimensional screening problem. This technique can provide some useful insights into the structure of...

Casual empiricism suggests higher quality is associated with greater variety. However, recent theoretical and empirical research has either not considered this link, or has been unable to establish unambiguous predictions about the relationship between quality and variety. In this paper we...