Results 11 to 20 of about 369,821 (215)
On complementable operators in the sense of T. Ando [PDF]
, 2020 Consider an operator A :H→K between Hilbert spaces and closed subspaces S ⊂ H and T ⊂ K. If there exist projections E on H and F on K such that R(E) =S, R(F) =T and AE=F∗A then A is called (S, T)-complementable.
Arias, Maria Laura +2 more
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Sard's approximation processes and oblique projections [PDF]
, 2009 Three problems arising in approximation theory are studied. These problems have already been studied by Arthur Sard. The main goal of this paper is to use geometrical compatibility theory to extend Sard's results and get characterizations of the sets of ...
Corach, Gustavo +2 more
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Random series in Lp(X, Σ,μ) using unconditional basic sequences and lp stable sequences: A result on almost sure almost everywhere convergence [PDF]
, 2007 Here we study the almost sure almost everywhere convergence of random series of the form Σ∞ i=1αifi in the Lebesgue spaces L p(X, Σ,μ), where the ai's are centered random variables, and the fi's constitute an unconditional basic sequence or an lp stable ...
Cernuschi Frias, Bruno +1 more
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Robust dual reconstruction systems and fusion frames [PDF]
, 2011 We study the duality of reconstruction systems, which are g-frames in a finite dimensional setting. These systems allow redundant linear encoding-decoding schemes implemented by the so-called dual reconstruction systems. We are particularly interested in
Massey, Pedro Gustavo +2 more
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Inequalities related to Bourin and Heinz means with a complex parameter [PDF]
, 2015 A conjecture posed by S. Hayajneh and F. Kittaneh claims that given A, B positive matrices, 0≤t≤1, and any unitarily invariant norm the following inequality holds{triple vertical-rule fence}AtB1-t+BtA1-t{triple vertical-rule fence}≤{triple vertical-rule ...
Bottazzi, Tamara Paula +3 more
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Differential structure of the Thompson components of selfadjoint operators [PDF]
, 2008 Different equivalence relations are defined in the set L(H)s of self- adjoint operators of a Hilbert space H in order to extend a very well known relation in the cone of positive operators.
Fongi, Guillermina +1 more
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Schur complements in Krein spaces [PDF]
, 2007 The aim of this work is to generalize the notions of Schur complements and shorted operators to Krein spaces. Given a (bounded) J-selfadjoint operator A (with the unique factorization property) acting on a Krein space H and a suitable closed subspace S ...
Maestripieri, Alejandra Laura +1 more
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Oblique projections and frames [PDF]
, 2006 We characterize those frames on a Hilbert space H which can be represented as the image of an orthonormal basis by an oblique projection defined on an extension K of H.
Antezana, Jorge Abel +3 more
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A note on the star order in Hilbert spaces [PDF]
, 2010 We study the star order on the algebra L(H) of bounded operators on a Hilbert space H. We present a new interpretation of this order which allows to generalize to this setting many known results for matrices: functional calculus, semi-lattice properties,
Antezana, Jorge Abel +3 more
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Metric geodesics of isometries in a Hilbert space and the extension problem [PDF]
, 2007 We consider the problem of finding short smooth curves of isometries in a Hilbert space H. The length of a smooth curve γ(t), t ∈ [0, 1], is measured by means of ∫^1-0 γ^. (t)ǀǀ dt, where ǀǀ ǀǀ denotes the usual norm of operators.
Andruchow, Esteban +2 more
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