An information-theoretical approach to a system of interacting elements

The maximum-entropy principle in information theory is generalized to include the interaction between elements of the system. A complex relation between the probabilities of the events is derived using a familiar technique in statistical mechanics. The relation is explicitly discussed for the case of bilinear interaction and only two events. Quite noteworthy is the existense in the system of a kind of “phase transition” similar to ferromagnetism. The result is applied to the mass behaviour. It is shown that the cooperative mass behaviour such as boom and fashion may be interpreted as a phase transition which would occur below certain “informational temperature”.