ON THE NUMERICAL RANGE WITH RESPECT TO A FAMILY OF PROJECTIONS

Dada W., Kerner J., ERKURŞUN ÖZCAN N.

METHODS OF FUNCTIONAL ANALYSIS AND TOPOLOGY, cilt.24, sa.4, ss.297-304, 2018 (ESCI) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 24 Sayı: 4
  • Basım Tarihi: 2018
  • Dergi Adı: METHODS OF FUNCTIONAL ANALYSIS AND TOPOLOGY
  • Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus
  • Sayfa Sayıları: ss.297-304
  • Hacettepe Üniversitesi Adresli: Evet

Özet

In this note we introduce the concept of a numerical range of a bounded linear operator on a Hilbert space with respect to a family of projections. We give a precise definition and elaborate on its connection to the classical numerical range as well as to generalizations thereof such as the quadratic numerical range, block numerical range, and product numerical range. In general, the importance of this new notion lies within its unifying aspect.