Remarks on Complemented Subspaces of Von-neumann Algebras*

نویسنده

  • Gilles Pisier
چکیده

In this note we include two remarks about bounded (not necessarily contractive) linear projections on a von Neumann-algebra. We show that if M is a von Neumann-subalgebra of B(H) which is complemented in B(H) and isomorphic to M ⊗ M then M is injective (or equivalently M is contractively complemented). We do not know how to get rid of the second assumption on M. In the second part,we show that any complemented reflexive subspace of a C *-algebra is necessarily linearly isomorphic to a Hilbert space.

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تاریخ انتشار 1992