In this paper we propose and implement numerical methods to detect exponential dichotomy on the real line. Our algorihtms are based on the singular value decomposition and the QR factorization of a fundamental matrix solution. The theoretical justification for our methods was laid down in the companion paper [15].

A classical result by Cauchy defines a disk containg all the zeros of a polynomial. We derive several related results by using similarity transformations of a polynomial’s companion matrix, together with Gershgorin’s theorem. We thus show that Cauchy’s original result can be seen as but one member of a family of related results. MathEduc Subject Classification: H35 MSC Subject Classification: 9...

We determine the p-rank of the incidence matrix of hyperplanes of PG(n, p) and points of a nondegenerate Hermitian variety. As a corollary, we obtain new bounds for the size of caps and the existence of ovoids in finite unitary spaces. This paper is a companion to [2], in which Blokhuis and this author derive the analogous p-ranks for quadrics.

Scalar linear time-varying systems are addressed. In particular, a new factorization method for the associated scalar polynomial system differential operator is presented. It differs from the classical results due to Cauchy and Floquet, in that it is based upon successive Riccati transformations of the Frobenius companion system matrix. As a consequence, the factorization is obtained in terms o...

If a system is given by its transfer function then the stability of the system is determined hy the denominator polynomial and its corresponding Hurwitz matrix 7-{. Also the critical stability conditions are determined by its determinant det 7-{. The aim of this paper is to get a generalized Hurwitz matrix for polynomial matrices. In order to achieve that, we first obtain a relation between the...

Continuous extensions are now routinely provided by many IVP solvers, for graphical output, error control, or event location. Recent developments suggest that a uniform, stable and convenient interpolant may be provided directly by value and derivative data (Hermite data), because a new companion matrix for such data allows stable, robust and convenient root-finding by means of (usually built-i...

In recent times increasing occurrence of dermatophytosis, especially among the school children in eastern India was evidenced along with increased tendency of keeping companion animals such as dogs and cats. This study was undertaken to detect the occurrence of dermatophytes with antifungal susceptibility among the companion animals. A total of 1501 healthy companion animals comprising 1209 dog...

The eigenvalues of a matrix polynomial can be determined classically by solving a generalized eigenproblem for a linearized matrix pencil, for instance by writing the matrix polynomial in companion form. We introduce a general scaling technique, based on tropical algebra, which applies in particular to this companion form. This scaling, which is inspired by an earlier work of Akian, Bapat, and ...