@article{0c5719deefc740d8b8a1643d523f36cc,

title = "Block Toeplitz operators with frequency-modulated semi-almost periodic symbols",

abstract = "This paper is concerned with the influence of frequency modulation on the semi-Fredholm properties of Toeplitz operators with oscillating matrix symbols. The main results give conditions on an orientation-preserving homeomorphism a of the real line that ensure the following: if b belongs to a certain class of oscillating matrix functions (periodic, almost periodic, or semi-almost periodic matrix functions) and the Toeplitz operator generated by the matrix function b (x) is semi-Fredholm, then the Toeplitz operator with the matrix symbol b (a (x)) is also semi-Fredholm.",

author = "A. B{\"o}ttcher and S. Grudsky and I. Spitkovsky",

note = "Funding Information: B{\"o}ttcher A. aboettch@mathematik.tu-chemnitz.de 1 Grudsky S. grudsky@math.cinvestav.mx 2 Spitkovsky I. ilya@math.wm.edu 3 1 Fakult{\"a}t f{\"u}r Mathematik TU Chemnitz Chemnitz 09107 Germany tu-chemnitz.de 2 Departamento de Matematicas CINVESTAV del IPN Aportado Postal 14-740 M{\'e}xico, DF 07360 Mexico cinvestav.mx 3 Department of Mathematics The College of William and Mary Williamsburg, VA 23187-8795 USA wm.edu 2003 17 06 2003 2003 34 2157 2176 23 07 2001 19 02 2002 2003 Copyright {\textcopyright} 2003 Hindawi Publishing Corporation This paper is concerned with the influence of frequency modulation on the semi-Fredholm properties of Toeplitz operators with oscillating matrix symbols. The main results give conditions on an orientation-preserving homeomorphism α of the real line that ensure the following: if b belongs to a certain class of oscillating matrix functions (periodic, almost periodic, or semi-almost periodic matrix functions) and the Toeplitz operator generated by the matrix function b ( x ) is semi-Fredholm, then the Toeplitz operator with the matrix symbol b ( α ( x ) ) is also semi-Fredholm. http://dx.doi.org/10.13039/501100003141 Consejo Nacional de Ciencia y Tecnolog{\'i}a 010286 http://dx.doi.org/10.13039/100000001 National Science Foundation DMS 9988579 ",

year = "2003",

doi = "10.1155/S0161171203107107",

language = "English (US)",

volume = "2003",

pages = "2157--2176",

journal = "International Journal of Mathematics and Mathematical Sciences",

issn = "0161-1712",

publisher = "Hindawi Publishing Corporation",

number = "34",

}