Fuzzy logic in economic models

Models of economic behavior are based on the search for and establishing of relationships between the various economic variables included in the model. Generally speaking, those coefficients that appear in relationships between the model variables are specific values that are determined when the model is to be used to make a given prediction. In this article we propose incorporating fuzzy logic into the study of economic models via the incorporation of fuzzy numbers to express the coefficients relating the different variables. To develop this idea, we analyze a simplified model for determining national income in which it is assumed that, for the sake of equilibrium, said value is composed of consumption and investment. Also, by relating the consumption function to income, we analyze a relationship model between the variables. To obtain broader and more real information than that resulting from the application of classical models, we incorporate fuzzy logic by assuming the parameters that establish the degree of dependence between the variables to be fuzzy numbers with a known membership function. Depending on their form, we determine their respective membership function for national income.