How an input series enters the model is called its transfer function. Thus, ARIMA models with input series are sometimes referred to as transfer function models. In the preceding regression and ...

For a rational matrix function Φ with poles outside the unit circle, we estimate the degree of the unique superoptimal approximation 𝒜Φ by matrix functions analytic in the unit disk. We obtain sharp ...

From the Maclaurin expansion of a function f̄(p) of the Laplace transform operator p, rational function approximations to f̄(p) are generated by means of a new nonlinear sequence to sequence ...