We study the dual formulation of the utility maximization problem in incomplete markets when the utility function is finitely valued on the whole real line. We extend the existing results in this literature in two directions. First, we allow for nonsmooth utility functions, so as to include the...

In this paper, we prove a multidimensional extension of the so-called Bipolar Theorem proved in Brannath and Schachermayer (Séminaire de Probabilités, vol. XXX, 1999, p. 349), which says that the bipolar of a convex set of positive random variables is equal to its closed, solid convex hull....

We consider a financial model with permanent price impact. Continuous time trading dynamics are derived as the limit of discrete rebalancing policies. We then study the problem of super-hedging a European option. Our main result is the derivation of a quasi-linear pricing equation. It holds in...

We consider a general multivariate financial market with transaction costs as in Kabanov and we analyse the stochastic control problems of maximizing the expected utility of the liquidation value of terminal wealth diminished by some random claim G for a utility function of exponential form.

We consider a financial market consisting of a nonrisky asset and a risky one. We study the minimal initial capital needed in order to super-replicate a given contingent claim under the Gamma constraint, i.e. a constraint on the unbounded variation part of the hedging porfolio. In the general...