m at h . FA ] 4 J an 2 00 5 A Survey on the Complemented Subspace Problem ∗
نویسنده
چکیده
The complemented subspace problem asks, in general, which closed subspaces M of a Banach space X are complemented; i.e. there exists a closed subspace N of X such that X = M ⊕N? This problem is in the heart of the theory of Banach spaces and plays a key role in the development of the Banach space theory. Our aim is to investigate some new results on complemented subspaces, to present a history of the subject, and to introduce some open problems. ∗2000 Mathematics Subject Classification. Primary 46B20; secondary 46B25, 46B28, 46B15, 46E30.
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