A criterion for uniqueness of a critical point in \(H_ 2\) rational approximation
This paper presents a criterion for uniqueness of a critical point in \(H_{2, R}\) rational approximation of type \((m,n)\), with \(m\geq n-1\). This criterion is differential-topological in nature, and turns out to be connected with corona equations and classical interpolation theory. This paper also gives its use with three examples, namely best approximation of fixed type on small circles, a de Montessus de Ballore type theorem, and diagonal approximation to the exponential function of large degree.
scientific article; zbMATH DE number 1019379
scientific article