Certain Banach-Space Operators Acting on Free Poisson Elements Induced by Orthogonal Projections

Author(s):  
Ilwoo Cho
2000 ◽  
Vol 43 (3) ◽  
pp. 511-528 ◽  
Author(s):  
Jörg Eschmeier

AbstractLet T and S be quasisimilar operators on a Banach space X. A well-known result of Herrero shows that each component of the essential spectrum of T meets the essential spectrum of S. Herrero used that, for an n-multicyclic operator, the components of the essential resolvent set with maximal negative index are simply connected. We give new and conceptually simpler proofs for both of Herrero's results based on the observation that on the essential resolvent set of T the section spaces of the sheavesare complete nuclear spaces that are topologically dual to each other. Other concrete applications of this result are given.


2017 ◽  
Vol 4 (1) ◽  
pp. 109-120
Author(s):  
Dijana Ilišević ◽  
Chih-Neng Liu ◽  
Ngai-Ching Wong

Abstract Being expected as a Banach space substitute of the orthogonal projections on Hilbert spaces, generalized n-circular projections also extend the notion of generalized bicontractive projections on JB*-triples. In this paper, we study some geometric properties of JB*-triples related to them. In particular, we provide some structure theorems of generalized n-circular projections on an often mentioned special case of JB*-triples, i.e., Hilbert C*-modules over abelian C*-algebras C0(Ω).


Author(s):  
Edwin Franks

AbstractIn Banach space operators with a bounded H∞ functional calculus, Cowling et al. provide some necessary and sufficient conditions for a type-ω operator to have a bounded H∞ functional calculus. We provide an alternate development of some of their ideas using a modified Cauchy kernel which is L1 with respect to the measure ]dz]/]z]. The method is direct and has the advantage that no transforms of the functions are necessary.


2013 ◽  
Vol 77 (3) ◽  
pp. 371-384 ◽  
Author(s):  
Pietro Aiena ◽  
Jesús R. Guillén ◽  
Pedro Peña

2008 ◽  
Vol 50 (1) ◽  
pp. 17-26 ◽  
Author(s):  
THOMAS L. MILLER ◽  
VLADIMIR MÜLLER

AbstractLetTbe a bounded operator on a complex Banach spaceX. LetVbe an open subset of the complex plane. We give a condition sufficient for the mappingf(z)↦ (T−z)f(z) to have closed range in the Fréchet spaceH(V,X) of analyticX-valued functions onV. Moreover, we show that there is a largest open setUfor which the mapf(z)↦ (T−z)f(z) has closed range inH(V,X) for allV⊆U. Finally, we establish analogous results in the setting of the weak–* topology onH(V, X*).


Filomat ◽  
2013 ◽  
Vol 27 (7) ◽  
pp. 1297-1303
Author(s):  
M.H.M. Rashid ◽  
T. Prasad

In this paper, we find necessary and sufficient conditions for Banach Space operator to satisfy the property (Bb). Then we obtain, if Banach Space operators A ? B(X)and B ? B(Y) satisfy property (Bb) implies A x B satisfies property (Bb) if and only if the B-Weyl spectrum identity ?BW(A x B) = ?BW(A)?(B) U ?BW(B)?(A) holds. Perturbations by Riesz operators are considered.


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