In the classical regression model with fixed regressors the statistic S 2 , i.e. the sum of squared residuals (SSR) divided by the number of degrees of freedom, is an unbiased estimator of the variance of the disturbances. If the model is dynamic and contains lagged-dependent explanatory...

This paper deals with a constructive approach for finding local approximations to singular perturbation problems. This approach is based on Nipp polyhedron algorithm wherein a correspondence between a singularly perturbed system and a convex polyhedron is established. The task of finding local...