کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4622790 1339505 2006 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The intersection of essential approximate point spectra of operator matrices
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات آنالیز ریاضی
پیش نمایش صفحه اول مقاله
The intersection of essential approximate point spectra of operator matrices
چکیده انگلیسی

When A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite-dimensional separable Hilbert space H⊕K of the form . In this paper, it is shown that there exists some operator C∈B(K,H) such that MC is upper semi-Fredholm and ind(MC)⩽0 if and only if there exists some left invertible operator C∈B(K,H) such that MC is upper semi-Fredholm and ind(MC)⩽0. A necessary and sufficient condition for MC to be upper semi-Fredholm and ind(MC)⩽0 for some C∈Inv(K,H) is given, where Inv(K,H) denotes the set of all the invertible operators of B(K,H). In addition, we give a necessary and sufficient condition for MC to be upper semi-Fredholm and ind(MC)⩽0 for all C∈Inv(K,H).

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Mathematical Analysis and Applications - Volume 323, Issue 2, 15 November 2006, Pages 1171-1183