Abstract
In this paper, new results are obtained concerning the uniform approximation property (UAP) inL p-spaces (p≠2,1,∞). First, it is shown that the “uniform approximation function” does not allow a polynomial estimate. This fact is rather surprising since it disproves the analogy between UAP-features and the presence of “large” euclidian subspaces in the space and its dual. The examples are translation invariant spaces on the Cantor group and this extra structure permits one to replace the problem with statements about the nonexistence of certain multipliers in harmonic analysis. Secondly, it is proved that the UAP-function has an exponential upper estimate (this was known forp=1, ∞). The argument uses Schauder’s fix point theorem. Its precise behaviour is left unclarified here. It appears as a difficult question, even in the translation invariant context.
Similar content being viewed by others
References
J. Bourgain and L. Tzafriri,Invertibility of large submatrices with applications to the geometry of Banach spaces, Israel J. Math.57 (1987), 137–224.
T. Figiel, W.B. Johnson and G. Schechtman,Factorizations of natural embeddings of l np into Lr, I, Studia Math.89 (1988), 79–103.
E. Gluskin, N. Tomczak-Jaegermann and L. Tzafriri,Subspaces of l Np of small codimension, Israel J. Math., this issue.
W.B. Johnson and G. Pisier,The proportional UAP characterizes weak Hilbert spaces, to appear.
W.B. Johnson and G. Schechtman,On subspaces of L 1 with maximal distance to Euclidian spaces, Proc. Workshop on Banach Space Theory (Bor-Luh-Lin, ed.), Univ. Iowa Press, 1981, pp. 83–96.
H.E. Lacey,The Isometric Theory of Classical Banach Spaces, Springer-Verlag, Berlin, 1974.
V. Mascioni,On the duality of the uniform approximation property in Banach spaces, Illinois J. Math.35 (1991), 191–197.
I.P. Nathanson,Constructive Function Theory, Vol. II, F. Ungar Publ. Co., New York, 1965.
G. Pisier,Holomorphic semigroups and the geometry of Banach spaces, Ann. of Math.115 (1982), 375–392.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bourgain, J. A remark on the behaviour ofL p-multipliers and the range of operators acting onL p-spaces. Israel J. Math. 79, 193–206 (1992). https://doi.org/10.1007/BF02808215
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02808215