کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8900335 | 1631560 | 2018 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Fredholmness of a linear combination of operators
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
ریاضیات
آنالیز ریاضی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Although it is well known that Fredholmness of the linear combination αP+βQ, α,βâCâ{0}, α+βâ 0, does not depend on the choice of scalars if P,QâB(H) are idempotents, no necessary and sufficient conditions for Fredholmness of this linear combination are yet known, except for the special case when P and Q are orthogonal projectors. In this paper, using a completely different approach and some results on completion problems of operator matrices, we give necessary and sufficient conditions for Fredholmness of a sum of two idempotents. Also, we will discuss the more general question when the sum of two operators is a Fredholm operator and consider some special cases when Fredholmness of a linear combination of two operators is independent of the choice of the scalars. On the other hand some special classes of operators for which a linear combination of two operators depends of the choice of the scalars are listed. A new proof of a well-known result is given.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Mathematical Analysis and Applications - Volume 458, Issue 1, 1 February 2018, Pages 555-565
Journal: Journal of Mathematical Analysis and Applications - Volume 458, Issue 1, 1 February 2018, Pages 555-565
نویسندگان
D. CvetkoviÄ-IliÄ, J. MiloÅ¡eviÄ,