A formula for <IMG >-hyponormality of backstep extensions of subnormal weighted shifts期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

A formula for -hyponormality of backstep extensions of subnormal weighted shifts

Authors:	Il Bong Jung Chunji Li

Affiliation:	Department of Mathematics, Kyungpook National University, Taegu 702--701, Korea ; Department of Mathematics, Yanbian University, Yanji 133-002, People's Republic of China

Abstract:	Let ${alpha }: {alpha }_{0}, {alpha }_{1}, cdots$ be a weight sequence of positive real numbers and let $W_{{alpha }}$ be a subnormal weighted shift with a weight sequence . Consider an extended weight sequence ${alpha }(x) : x, {alpha }_{0}, {alpha }_{1}, cdots$ with $0<x le alpha _{0}$ and let $HE({alpha ,k}):= { x >0: W_{alpha (x)} text{is} k text{-hyponormal}}$ for , where is the set of natural numbers. We obtain a formula to find the interval , which provides several examples to distinguish the classes of -hyponormal operators from one another.

Keywords:	Subnormal weighted shifts $k$-hyponormal weighted shifts

	点击此处可从《Proceedings of the American Mathematical Society》浏览原始摘要信息
	点击此处可从《Proceedings of the American Mathematical Society》下载全文