(1) Dept. of Math & Stats, Univ. of Saskatchewan, S7N 5E6 Saskatoon, SK, CANADA;(2) Dept. of Math & Stats, Univ. of Saskatchewan, S7N 5E6 Saskatoon, SK, CANADA;(3) Dept. of Chemistry, Univ. of Saskatchewan, S7N 5C9 Saskatoon, SK, CANADA
Abstract:
We show that ifT(F) is a selfadjoint block Toeplitz operator generated by a trigonometric matrix polynomialF, then the spectrum ofT(F) as well as the limiting set (F) of the eigenvalues of the truncationsTn(F) is the union of a finite collection of segments (the spectral range ofF) and at most a finite set of points for which we give an upper bound.