Approximation of N∞ κ -functions I : Models and regularization
The class N∞ κ consists of all generalized Nevanlinna functions N with κ negative squares for which the root space at ∞ of the self-adjoint relation in the minimal model (short for self-adjoint operator realization) of N contains a κ-dimensional non-positive subspace. In this paper we discuss two specific models for the function N ∈ N∞ κ: one associated with the irreducible representation of N and
