The aim of this paper is to present a search model in the field of environmental economics, where so-called clean and dirty producers enter the trading market, both looking for a partner with whom to exchange the goods they are endowed with. The model derived in this paper is rather simple....

A model of different species competing for the same environment is presented, and possible explanations of peaceful coexistence or rather internecine conflicts are consequently derived. By means of a Lotka-Volterra dynamic system we describe the evolution of two populations (bees and locusts)...

The notion of sustainability represents the core of the theoretical and political debate on the potential conflict between economic growth and environmental quality. A clear definition of what sustainability means, although still controversial, is indeed a possible keystone to better...