Showing papers by "William Desmond Evans published in 1997"

Approximate diagonalization in differential systems and an effective algorithm for the computation of the spectral matrix

Abstract: This paper reports on recent work to compute the asymptotic solution of a n-th order ordinary differential equation. Symbolic methods are used to compute the asymptotics over a large region. Application is made to the computation of the Titchmarsh-Weyl M-matrix for the fourth order operator.

On the spectrum of second order differential operators with complex coefficients

Abstract: The Weyl-Sims classification for a second-order ordinary differential equation with general complex coefficients is investigated. Connections are then established between the associated m-function and the spectral properties of maximal-accretive realisations of the differential expression.