简介：LetB(H)bethealgebraofalltheboundedlinearoperatorsonaHilbertspaceH.ForA,PandQinB(H),ifthereexistsanoperatorX∈B(H)suchthatAPXQA=A,XQAPX=X,(QAPX)*=QAPXand(XQAP)*=XQAP,thenXissaidtobetheΓ-inverseofAassociatedwithPandQ,anddenotedbyAP,Q+.Inthisnote,wepresentsomenecessaryandsu?cientconditionsforwhichA+P,Qexists,andgiveanexplicitrepresentationofAP,Q+(ifAP,Q+exists).

简介：Thestudyofoperatorssatisfyingσja(T)=σa(T)isofsignificantinterest.Doesσja(T)=σa(T)forn-perinormaloperatorT∈B(H)ffThisquestionwasraisedbyMecheriandBraha[Oper.Matrices6(2012),725–734].Inthenoteweconstructacounterexampletothisquestionandobtainthefollowingresult:ifTisan-perinormaloperatorinB(H),thenσja(T)\{0}=σa(T)\{0}.Wealsoconsidertensorproductofn-perinormaloperators.

简介：DellaVecchiaetal.(see[2])introducedakindofmodifiedBernsteinoperatorswhichcanbeusedtoapproximatefunctionswithsingularitiesatendpointson[0,1]Inthepresentpaper,weobtainakindofpointwiseStechkin-typeinequalitiesforweightedapproximationbythemodifiedBernsetinoperators.

简介：InthispaperweproposetheqanaloguesofmodifiedBaskakov-Sz′aszoperators.Weestimatethemomentsandestablisheddirectresultsintermofmodulusofcontinuity.Anestimatefortherateofconvergenceandweightedapproximationpropertiesoftheqoperatorsarealsoobtained.

简介：Inthispaper,weobtainsomenewnecessaryandsuffcientconditionsfortheboundednessandcompactnessofcompositionoperatorsCφbetweenBlochtypespacesintheunitballBn.

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简介：Inthispaper,wewillprovetheboundednessofHardytypeoperatorsHβ(x)andH*β(x)ofvariableorderβ(x)onHerzspacesKα(·)p(·),qandKα(·)p(·),q’whereα(·)andp(·)arebothvariable.

简介：为>1，让d在bidisk和一项复杂措施上表示加权的Lebesgue措施令人满意一些Carleson类型条件。在这份报纸，我们为Toeplitz操作员$T_显示出一个足够、必要的条件{\bar\mu}在加权的Bergman空间L上要跳或压缩的^\alpha$一1(d)。

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简介：WeshowthatmanyharmonicanalysisoperatorsintheBesselsetting,includingmaximaloperators,Littlewood–Paley–Steintypesquarefunctions,multipliersofLaplaceorLaplace–StieltjestransformtypeandRiesztransformsare,orcanbeviewedas,Calderón–Zygmundoperatorsforallpossiblevaluesoftypeparameterλinthiscontext.Thisextendsresultsexistingintheliterature,butbeingjustifiedonlyforarestrictedrangeofλ.

简介：WestudytheboundedandthecompactweightedcompositionoperatorsfromtheBlochspaceintotheweightedBanachspacesofholomorphicfunctionsonboundedhomogeneousdomains,withparticularattentiontotheunitpolydisk.Forboundedhomogeneousdomains,wecharacterizetheboundedweightedcompositionoperatorsanddeterminetheoperatornorm.Inaddition,weprovidesufficientconditionsforcompactness.Fortheunitpolydisk,wecompletelycharacterizethecompactweightedcompositionoperators,aswellasprovide'computable'estimatesontheoperatornorm.