The use of complex variable functions in economic and mathematical models, using the example of the international trade model of the Visegrad four countries for 2000-2015

Interpolation of time series by the sum of exponents of a function of a complex variable gives an approximation no worse than using regression analysis. Despite the fact that time series are interpolated by functions of a complex variable, the values of these functions under certain conditions are real numbers. The imaginary component of complex numbers that occurs during calculations is several orders of magnitude smaller than the real part . The appearance of the imaginary part is due , in the author 's opinion , to the error of calculations and it can be neglected when interpreting the result of calculations . To calculate the interpolating function, the author used standard procedures used in the MATHLAB software. The absence of extremum points for exponents is the main advantage when using exponent sums for interpolation purposes compared to interpolation by polynomials.