Restricted Invertibility and the Banach-mazur Distance to the Cube

نویسنده

  • PIERRE YOUSSEF
چکیده

We prove a normalized version of the restricted invertibility principle obtained by Spielman-Srivastava in [15]. Applying this result, we get a new proof of the proportional Dvoretzky-Rogers factorization theorem recovering the best current estimate in the symmetric setting while we improve the best known result in the nonsymmetric case. As a consequence, we slightly improve the estimate for the Banach-Mazur distance to the cube: the distance of every n-dimensional normed space from `∞ is at most (2n) 5 6 . Finally, using tools from the work of Batson-Spielman-Srivastava in [2], we give a new proof for a theorem of Kashin-Tzafriri [11] on the norm of restricted matrices.

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تاریخ انتشار 2013