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Isometric results on a measure of non-compactness for operators on Banach spaces

Published online by Cambridge University Press:  17 April 2009

S. J. Dilworth
Affiliation:
Department of Mathematics, The University of Texas at Austin, Austin, Texas 78712, United States of America.
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Abstract

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For each λ ≥ 1 a class of Banach spaces φλ is defined. Isometric results are obtained on the equivalence between a measure of non-compactness and the essential norm of a linear operator defined on a φλ space. Best values of λ for the classical Banach spaces and for spaces with unconditional basis are investigated. For the space c of convergent sequences the non-existence of a λ-unconditional basis with λ < 2 is deduced.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1987

References

[1]Astala, K. and Tylli, H.-O., “On bounded compactness property and measures of non-compactness”, J. Funct. Anal. (to appear).Google Scholar
[2]Banach, S., Théorie des Opérations Linéaries (Second Edition), Chelsea Publishing Company, New York, 1978.Google Scholar
[3]Cambern, M., “On mappings of sequence spaces”, Studia Math. 30 (1968), 73–44.CrossRefGoogle Scholar
[4]Davis, W.J., “Remarks on finite rank projections”, J. Approx. Theory 9 (1973), 205211.CrossRefGoogle Scholar
[5]Hutton, C.V., “On the approximation numbers of an operator and its adjoint”, Math. Ann. 210 (1974), 277280.CrossRefGoogle Scholar
[6]Johnson, W.B., Rosenthal, H.P. and Zippin, M., “On bases, finite dimensional decompositions and weaker structures in Banach spaces”, Israel J. Math. 9 (1971), 488506.Google Scholar
[7]Lebow, A. and Schechter, M., “Semigroups of operators and measure of non-compactness”, J. Funct. Anal. 7 (1971), 126.CrossRefGoogle Scholar
[8]Lindenstrauss, J. and Tzafriri, L., Classical Banach spaces I, Springer-Verlag, 1977.Google Scholar
[9]Lindenstrauss, J. and Pelczyński, A., “Contributions to the theory of the classical Banach spaces, J. Funct. Anal. 8 (1971), 225249.Google Scholar