The numerical range of a nilpotent operator on a Hilbert space
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY, cilt.132, sa.8, ss.2321-2326, 2004 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 132 Sayı: 8
- Basım Tarihi: 2004
- Doi Numarası: 10.1090/s0002-9939-04-07391-5
- Dergi Adı: PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.2321-2326
- Süleyman Demirel Üniversitesi Adresli: Hayır
Özet
We prove that the numerical range W (N) of an arbitrary nilpotent operator N on a complex Hilbert space H is a circle ( open or closed) with center at 0 and radius not exceeding parallel toNparallel to cos pi/n+1; where n is the power of nilpotency of N.