×

Contractibility of compact contractions in Hilbert space. (English) Zbl 0999.15010

A necessary and sufficient condition for the spectral radius of a compact contraction being less than one is stated.
Let \(\Sigma\) denote a finite set of compact contractions on a complex Hilbert space. Then the spectral radius of \(A\) is less than one for all \(A\) in the multiplicative semigroup generated by \(\Sigma\) if and only if there exists a positive integer \(N\) such that norm of \(A\) is less than one for all \(A\) in the set of all products of operators in \(\Sigma\) of length \(N\).
Related extensions and examples are considered.

MSC:

15A18 Eigenvalues, singular values, and eigenvectors
47A10 Spectrum, resolvent
47B07 Linear operators defined by compactness properties
15A42 Inequalities involving eigenvalues and eigenvectors
15A60 Norms of matrices, numerical range, applications of functional analysis to matrix theory
Full Text: DOI

References:

[1] Ando, T.; Shih, M.-H., Simultaneous contractibility, SIAM J. Matrix Anal. Appl., 19, 487-498 (1998) · Zbl 0912.15033
[2] Berger, M. A.; Wang, Y., Bounded semigroups of matrices, Linear Algebra Appl., 166, 21-27 (1992) · Zbl 0818.15006
[3] Colella, D.; Heil, C., The characterization of continuous, four-coefficient scaling functions and wavelets, IEEE Trans. Inform. Theory, 38, 876-881 (1992) · Zbl 0743.42012
[4] Colella, D.; Heil, C., Characterizations of scaling functions: continuous solutions, SIAM J. Matrix Anal. Appl., 15, 496-518 (1994) · Zbl 0797.39006
[5] Daubechies, I.; Lagarias, J. C., Two-scale difference equations. I. Existence and global regularity of solutions, SIAM J. Math. Anal., 22, 1388-1410 (1991) · Zbl 0763.42018
[6] Daubechies, I.; Lagarias, J. C., Two scale difference equations. II. Local regularity, infinite products of matrices and fractals, SIAM J. Math. Anal., 23, 1031-1079 (1992) · Zbl 0788.42013
[7] Daubechies, I.; Lagarias, J. C., Sets of matrices all infinite products of which converge, Linear Algebra Appl., 161, 227-263 (1992) · Zbl 0746.15015
[8] Halmos, P. R., A Hilbert Space Problem Book (1982), Springer: Springer New York, revised and enlarged · Zbl 0496.47001
[9] Jacobson, N., Structure of Rings (1964), AMS: AMS Providence, RI
[10] Lagarias, J. C.; Wang, Y., The finiteness conjecture for the generalized spectral radius of a set of matrices, Linear Algebra Appl., 214, 17-42 (1995) · Zbl 0818.15007
[11] Rota, G.-C.; Strang, G., A note on the joint spectral radius, Indag. Math., 22, 379-381 (1960) · Zbl 0095.09701
[12] Shih, M.-H.; Wu, J.-W.; Pang, C.-T., Asymptotic stability and generalized Gelfand spectral radius formula, Linear Algebra Appl., 252, 61-70 (1997) · Zbl 0873.15012
[13] Taylor, A. E.; Lay, D. C., Introduction to Functional Analysis (1980), Wiley: Wiley New York · Zbl 0501.46003
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.