Parameter influence on the zeros of network determinants

To a network with determinant Δ(s;q) depending on a parameter vector via identification of some of its vertices, a network is assigned. The paper deals with procedures to find , such that its determinant admits a factorization in the determinants of appropriate subnetworks, and with the estimation of the deviation of the zeros of from the zeros of Δ. To solve the estimation problem state space methods are applied.