Unbounded 2-hyperexpansive operators

被引:37
作者
Jablonski, ZJ [1 ]
Stochel, J [1 ]
机构
[1] Jagiellonian Univ, Inst Matemat, PL-30059 Krakow, Poland
关键词
unbounded operators; closedness of powers of operators; 2-hyperexpansive operators; 2-isometries; paranormal operators; weighted shifts;
D O I
10.1017/S001309159900139X
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
It is shown that most properties of (bounded) completely hyperexpansive operators remain valid for unbounded 2-hyperexpansive operators. Powers of closed 2-hyperexpansive operators are proved to be closed and 2-hyperexpansive. Various parts of spectra of such operators are calculated. 2-hyperexpansive weighted shifts are investigated. Examples of unbounded closed 2-hyperexpansive (2-isometric) operators with invariant dense domains are established.
引用
收藏
页码:613 / 629
页数:17
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