SEPARATION OF ROOTS OF MATRIX AND OPERATOR POLYNOMIALS

Authors
Citation
Y. Lyubich, SEPARATION OF ROOTS OF MATRIX AND OPERATOR POLYNOMIALS, Integral equations and operator theory, 29(1), 1997, pp. 52-62
Citations number
12
Categorie Soggetti
Mathematics, Pure",Mathematics,Mathematics
ISSN journal
0378620X
Volume
29
Issue
1
Year of publication
1997
Pages
52 - 62
Database
ISI
SICI code
0378-620X(1997)29:1<52:SOROMA>2.0.ZU;2-I
Abstract
In a complex Hilbert space X for an arbitrary operator polynomial L(la mbda) (lambda is an element of C) of degree m the following theorem is proved. If the equation (L(lambda)x, x) = 0 has m distinct roots at e very point x is an element of X, \\x\\ = 1, then there exist m pairwis e disjoint connected sets in C such that each set contains a root at e very x. The minimal distance between the roots is separated from zero under the same assumption on the discriminant and the leading coeffici ent of that equation.