This article is a short survey of the notion of a collectively compact set of operators. A glimpse of basic results in the field with relevant references has been provided. As an application of this concept a theorem of Nayak, strengthening a result of Yamamoto, has been extended from matrices to compact operators. It is proved that if A is a compact operator on a complex separable Hilbert space then \(|A^n|^{\frac{1}{n}}\) converges in norm to some positive operator as n tends to infinity.

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

A Survey of Collectively Compact Sets of Operators and Compact Operator Version of Nayak’s Theorem

  • Neeru Bala,
  • B. V. Rajarama Bhat

摘要

This article is a short survey of the notion of a collectively compact set of operators. A glimpse of basic results in the field with relevant references has been provided. As an application of this concept a theorem of Nayak, strengthening a result of Yamamoto, has been extended from matrices to compact operators. It is proved that if A is a compact operator on a complex separable Hilbert space then \(|A^n|^{\frac{1}{n}}\) converges in norm to some positive operator as n tends to infinity.