Let M(X) be a family of all equivalent local martingale measures for some locally bounded d-dimensional process X, and V be a positive process. Main result of the paper (Theorem 2.1) states that the process V is a supermartingale whatever Q in M(X), if and only if this process admits the...

The rational expectations hypothesis is supported if rational expectations are stable with respect to reasonable learning procedures. We consider the Stochastic Gradient-Algorithm as a boundedly rational learning procedure in an univariate ARX-Model with forecast feedback. We prove that whenever...

In this study we consider a linear model with forecast feedback in which boundedly rational agents are learning the parameter values of the rational expectations equilibrium by the OLS learning procedure. We show strong consistency of the OLS estimates under much weaker assumptions on the...

In the framework of the classical Black and Scholes model of security market we present the explicit formulas of the minimal hedging portfolios for a number of reward processes of the ``classical'', lookback and Asian type. These results complement the solutions previously received by Mc~Kean,...

A term structure model with lognormal type volatility structure is proposed. The Heath, Jarrow and Morton (HJM) framework, coupled with the theory of stochastic evolution equations in infinite dimensions, is used to show that the resulting rates are well defined (they do not explode) and remain...

We develop a new approach to pricing and hedging contingent claims in incomplete markets. Mimicking as closely as possible in an incomplete markets framework the no--arbitrage arguments that have been developed in complete markets leads us to defining the concept of pseudo--arbitrage. Building...

Assuming constant interest rates Brennan and Schwartz (1976, 1979) obtained the rational insurance premium on an equity-linked insurance contract through the application of the theory of contingent claims pricing. Further considerations with deterministic interest rates have been discussed in...