A model of Brownian particles with the ability to take up energy from the environment, to store it in an internal depot, and to convert internal energy into kinetic energy of motion, is discussed. The general dynamics outlined in Section 2, is investigated for the deterministic and stochastic...

A stochastic theory is presented for nucleation and growth of clusters in a finite system. We consider a discrete cluster distribution for which the free energy and the equilibrium probability distribution are derived. The cluster growth and shrinkage occurs by the attachment/evaporation of free...

We study phase transitions in models of opinion formation which are based on the social impact theory. Two different models are discussed: (i) a cellular-automata-based model of a finite group with a strong leader where persons can change their opinions but not their spatial positions, and (ii)...

This paper investigates the agglomeration of active walkers (component A) on a two- dimensional surface, described by a potential U(r,t), that determines the motion of the walkers. The walkers are able to change U(rt) locally by producing a second component B, that decreases U(r,t) and which can...

We present analytical investigations of a multiplicative stochastic process that models a simple investor dynamics in a random environment. The dynamics of the investor’s budget, x(t), depends on the stochasticity of the return on investment, r(t), for which different model assumptions are...

For a binary choice problem, the spatial coordination of decisions in an agent community is investigated both analytically and by means of stochastic computer simulations. The individual decisions are based on different local information generated by the agents with a finite lifetime and...

We study the topological structure of the network of shareholding relationships in the Italian stock market (MIB) and in two US stock markets (NYSE and NASDAQ). The portfolio diversification and the wealth invested on the market by economical agents have been shown in our previous work to have...

Members of boards of directors of large corporations who also serve together on an outside board, form the so-called interlock graph of the board and are assumed to have a strong influence on each others’ opinion. We here study how the size and the topology of the interlock graph affect the...

We propose a network description of large market investments, where both stocks and shareholders are represented as vertices connected by weighted links corresponding to shareholdings. In this framework, the in-degree (kin) and the sum of incoming link weights (v) of an investor correspond to...