0000000000643165

AUTHOR

Eve Oja

Bounded approximation properties via integral and nuclear operators

Published version of an article in the journal:Proceedings of the American Mathematical Society. Also available from the publisher, Open Access

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Absolutely summing operators on C[0,1] as a tree space and the bounded approximation property

AbstractLet X be a Banach space. For describing the space P(C[0,1],X) of absolutely summing operators from C[0,1] to X in terms of the space X itself, we construct a tree space ℓ1tree(X) on X. It consists of special trees in X which we call two-trunk trees. We prove that P(C[0,1],X) is isometrically isomorphic to ℓ1tree(X). As an application, we characterize the bounded approximation property (BAP) and the weak BAP in terms of X∗-valued sequence spaces.

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Absolutely summing operators on C[0,1] as a tree space and the bounded approximation property

Abstract Let X be a Banach space. For describing the space P ( C [ 0 , 1 ] , X ) of absolutely summing operators from C [ 0 , 1 ] to X in terms of the space X itself, we construct a tree space l 1 tree ( X ) on X. It consists of special trees in X which we call two-trunk trees. We prove that P ( C [ 0 , 1 ] , X ) is isometrically isomorphic to l 1 tree ( X ) . As an application, we characterize the bounded approximation property (BAP) and the weak BAP in terms of X ∗ -valued sequence spaces.

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Bounded approximation properties via integral and nuclear operators

Published version of an article in the journal:Proceedings of the American Mathematical Society. Also available from the publisher, Open Access Let X be a Banach space and let A be a Banach operator ideal. We say that X has the lambda-bounded approximation property for A (lambda-BAP for A) if for every Banach space Y and every operator T is an element of A(X, Y), there exists a net (S-alpha) of finite rank operators on X such that S-alpha -> I-X uniformly on compact subsets of X and lim(alpha) sup parallel to TS alpha parallel to(A)<=lambda parallel to T parallel to(A). We prove that the (classical) lambda-BAP is precisely the lambda-BAP for the ideal I of integral operators, or equivalentl…

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