Variation of the Spectrum of Operators in Infinite Dimensional Spaces

• 作者: Mohammed Yahdi
• 来源期刊: 理论数学进展(英文)
• 学科: 数学
• 关键词: Operator SPECTRUM BOREL Function BANACH SPACE POLISH SPACE
• 年，卷（期）: 2013,（7）
• 页码范围: 621-624
• 页数: 4页
• 分类号: O1

摘要

The paper investigates the variation of the spectrum of operators in infinite dimensional Banach spaces. Consider the space of bounded operators on a separable Banach space when equipped with the strong operator topology, and the Polish space of compact subsets of the closed unit disc of the complex plane when equipped with the Hausdorff topology. Then, it is shown that the unit spectrum function is Borel from the space of bounded operators into the Polish space of compact subsets of the closed unit disc. Alternative results are given when other topologies are used.