趙小鵬,戴磊*,曹小紅
(1.渭南師范學(xué)院 數(shù)學(xué)與統(tǒng)計(jì)學(xué)院,陜西 渭南 714099;2.陜西師范大學(xué)數(shù)學(xué)與統(tǒng)計(jì)學(xué)院,陜西 西安 710119)
有界線性算子及其函數(shù)的(R)性質(zhì)
趙小鵬1,戴磊1*,曹小紅2
(1.渭南師范學(xué)院 數(shù)學(xué)與統(tǒng)計(jì)學(xué)院,陜西 渭南 714099;2.陜西師范大學(xué)數(shù)學(xué)與統(tǒng)計(jì)學(xué)院,陜西 西安 710119)
設(shè)為無限維復(fù)可分的Hilbert空間,為中有界線性算子的全體。若,則稱滿足性質(zhì),其中和分別表示算子的逼近點(diǎn)譜和Browder本質(zhì)逼近點(diǎn)譜,;若,則稱滿足性質(zhì)。給出了有界線性算子滿足性質(zhì)或性質(zhì)的充要條件,研究了算子函數(shù)滿足性質(zhì)或性質(zhì)的判定方法,并討論了完全*-paranormal算子及其函數(shù)的性質(zhì)或性質(zhì)。
性質(zhì);性質(zhì);譜
1909年,WEYL[1]發(fā)現(xiàn)Hilbert空間中自伴算子的Weyl譜恰等于該算子的譜集除去有限重的孤立特征值,即Weyl定理。之后,出現(xiàn)了許多Weyl定理的變形和推廣[2-4]。其中性質(zhì)是Weyl定理的一種變形,近年來備受關(guān)注[5-7]。本文繼續(xù)討論有界線性算子的性質(zhì)。
若
本文利用Weyl譜的一種變形,首先,給出有界線性算子滿足或性質(zhì)的充要條件;然后,利用該譜集,得到算子函數(shù)滿足性質(zhì)或性質(zhì)的判定方法;最后,作為應(yīng)用,研究完全*-paranormal算子及其函數(shù)的性質(zhì)或性質(zhì)。
令
令
證明同定理1。
令
令
證明 必要性。(1)顯然成立。
由定理3以及推論3,可得
由定理4及推論6,可得:
由定理4,可得:
將Weyl譜變形,定義了一個新的譜集。利用該新譜集,討論了有界線性算子及其函數(shù)的(R)性質(zhì),給出了有界線性算子及其函數(shù)滿足(R)性質(zhì)的充要條件。從所得結(jié)果中可看出(R)性質(zhì)與算子譜結(jié)構(gòu)之間的關(guān)系,并將結(jié)果應(yīng)用于研究完全*-paranormal算子及其函數(shù)滿足(R)性質(zhì)的判定方法。
[1]WEYL H V. über beschr?nkte quadratische formen, deren differenz vollstetig ist[J]. Rendiconti del Circolo Matematico di Palermo, 1909, 27:373-392. DOI:10.1007/BF03019655
[2]HARTE R, LEE W Y. Another note on Weylapos;s theorem[J]. Transactions of the American Mathematical Society, 1997,349(5): 2115-2124. DOI:10.1090/S0002-9947-97-01881-3
[3]RAKO?EVI? V. Operators obeying a-Weylapos;s theorem[J]. Revue Roumaine des Mathematiques Pures et Appliquees, 1989,34(10):915-919.
[4]RAKO?EVI? V. On a class of operators[J]. Matematicki Vesnik, 1985, 37(92):423-426.
[5]AIENA P, GUILLéN J R,PE?A P. Propertyfor bounded linear operators[J]. Mediterranean Journal of Mathematics, 2011,8(4): 491-508. DOI:10.1007/s00009-011-0113-0
[6]AIENA P, APONTE E,GUILLéN J R, et al. Propertyunder perturbations[J]. Mediterranean Journal of Mathematics, 2013,10(1): 367-382. DOI:10.1007/s00009-012-0174-8
[7]JIA B T, FENG Y L. Propertyunder compact perturbations[J]. Mediterranean Journal of Mathematics, 2020,17(2): 491-508. DOI:10. 1007/s00009-020-01506-6
[8]RADJAVI H, ROSENTHAL P. Invariant Subspaces[M]. Mineola: Dover Publications,2003.
Property (R) for bounded linear operator and its functions
ZHAO Xiaopeng1, DAI Lei1, CAO Xiaohong2
(1. School of Mathematics and Statistics,Weinan Normal University,Weinan714099,Shaanxi Province,China;2. School of Mathematics and Statistics,Shaanxi Normal University,Xiapos;an710119,China)
LetHbe an infinite dimensional complex separable Hilbert space andbe the algebra of all bounded linear operators onH.is said to satisfy propertyif, whereanddenote the approximate point spectrum and the Browder essential approximate point spectrum ofrespectively, and. If,is said to satisfy property. In this paper, we give the necessary and sufficient conditions for which the propertyor propertyholds for bounded linear operators. In addition, we characterize the judgements for operator functions satisfying propertyor propertyand explored the propertyor propertyfor totally *-paranormal operators.
property; property; spectrum
10.3785/j.issn.1008-9497.2022.03.005
O 177.2
A
1008?9497(2022)03?294?06
2021?01?19.
陜西省自然科學(xué)基金資助項(xiàng)目(2021JM-519);渭南師范學(xué)院人才項(xiàng)目(2021RC02).
趙小鵬(1968—),ORCID:https://orcid.org/0000-0003-3962-7006,男,碩士,副教授,主要從事算子理論與算子代數(shù)研究,E-mail:zxp@wnu.edu.cn.
通信作者,ORCID:https://orcid.org/0000-0003-3830-6980,E-mail:leidai@yeah.net.