SUMMARY In this paper we consider optimal trading processes in economic systems. The analysis is based on accounting for irreversibility factor using wealth function concept.

Numerous attempts have been made to identify the optimal mix of patent breadth and patent life. Unfortunately, the range of contradictory results reported in literature is rather impressive. The aim of this note is to develop a very stylised model that encompasses a variety of different findings, and to derive a general rule for the optimal patent policy. JEL classification: O34, O31.

In applications wide band noises are observed by autocovariance functions. At the same time there are infinitely many wide band noises having the same autocovariance function. Each of these wide band noises creates its own best estimate and optimal control. Therefore, it is practically important to obtain filtering and control results which depend on autocovariance function and independent on r...

We study the optimal domain for the Hardy operator considered with values in a rearrangement invariant space. In particular, this domain can be represented as the space of integrable functions with respect to a vector measure defined on a δ-ring. A precise description is given for the case of the minimal Lorentz spaces.