In this article, we characterize efficient portfolios, i.e. portfolios which are optimal for at least one rational agent, in a very general financial market model of foreign currencies with proportional transaction costs. In our setting, transaction costs may be random, time dependent, have...

In this article, we characterize efficient portfolios, i.e. portfolios which are optimal for at least one rational agent, in a very general financial market model of foreign currencies with proportional transaction costs. In our setting, transaction costs may be random, time dependent, have...

Investigations of long-run sustainability of joint ecological-economic systems highlight the pertinence of reconsidering "free disposal" assumptions that underpin Sraffian and von Neumann approaches to value and growth theory. We investigate joint-production time-paths for square systems A and B...

Severe environmental degradation appears to be threatening the long-term development prospects of countries all over the world, particularly the developing ones such as Nigeria. The paper reviews relevant literature and examines the process of environmental degradation via water pollution in...