A model for ideological struggles is formulated. The underlying set is a closed one, like a country but in which the population size is variable in time. The dynamics of the struggle is described by model equations of Verhulst–Lotka–Volterra kind. Several “ideologies” compete to increase...

We investigate an economic system in which one large agent—the Japan government changes the environment of numerous smaller agents—the Japan agriculture producers by indirect regulation of prices of agriculture goods. The reason for this intervention was that before the oil crisis in 1974...