ABSTRACT
The argument of Professor Paul A. Samuelson [18] that the problem of economics can be treated dynamically is now well known. He stresses that students of economics are often shut out from understanding much of modem economics if they have not mastered some amount of theory of dynamical systems. One studies the time evolution of economic vari ables. There are two choices of “time” to be used in the construction of dynamic modelscontinuous and discrete. The first leads to differential equations and the second to differ ence equations. Though both are useful, Gandolfo [12, 13] strongly suggests that mixed differential-difference equations are much more suitable than differential equations alone, or difference equations alone, for an adequate treatment of dynamic economic phenom ena. We shall therefore obtain and study continuous models and then mixed differentialdifference equations or functional differential systems. The systems quantitative behavior will be studied. Estimation of the parameters of the equations based on samples of discrete observations of several countries will be made. Some forecast will be attempted.
