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On Banach spaces, nonisomorphic to their Cartesian squares. (English. Russian original) Zbl 0844.46011
Math. Notes 57, No. 4, 369-374 (1995); translation from Mat. Zametki 57, No. 4, 534-541 (1995).
The first examples of Banach spaces, nonisomorphic to their Cartesian squares, have been given by C. Bessaga, A. Pełczyński [Bull. Acad. Polon. Sci. 8, No. 2, 77-80 (1960; Zbl 0091.27801)] and Z. Semadeni [ibid. 8, No. 2, 81-84 (1960; Zbl 0091.27802)]. An example of a reflexive space with this property has been constructed by T. Figiel [Studia Math. 42, No. 3, 295-306 (1972; Zbl 0213.12801)]. As shown by S. Szarek [Proc. Am. Math. Soc. 97, No. 3, 437-444 (1986; Zbl 0604.46019)], there exists a real Banach space that is not isomorphic to the Cartesian square of any Banach space. The fundamental result of the present paper is the following
Theorem. There exist reflexive Banach spaces $$X$$ and $$Y$$, nonisomorphic to their Cartesian squares but having the property that $$X\oplus Y$$ is isomorphic to its Cartesian square.
Reviewer: Reviewer (Berlin)
##### MSC:
 46B20 Geometry and structure of normed linear spaces
Full Text:
##### References:
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