Evaluating the order of connectivity and the degree of polynomial phenomenological equations from experimental data

We present an algorithm for constructing phenomenological recurrence equations for dynamic systems in the class of power polynomial; the construction is based on processing of measured values of an output signal under conditions ofa priori unknown order of connectivity and of nonlinearity (degree of the polynomial). We present estimates for the efficiency of the algorithm and confirm its correctness. As an example, we construct the equation for an electrocardiogram.