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SUMMARY:Explicit Euclidean Sections\, Codes over the Reals and Expanders -
  Wigderson\, A (IAS Princeton)
DTSTART:20110412T124500Z
DTEND:20110412T134500Z
UID:TALK30781@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Here is a basic problem\, which comes under various names incl
 uding "compressed sensing matrices"\, Euclidean sections of L1"\, "restric
 ted isometries"  and more. Find a subspace X or R^N such that every vector
  x in X has the same L1 and L2 norms (with proper normalization) up to con
 stant factors. It is known that such subspaces of dimension N/2 exist (ind
 eed "most" of them are)\, and the problem is to describe one explicitly.\n
 I will describe some progress towards this problem\, based on extending th
 e notion of expander codes from finite fields to the reals.\n\n
LOCATION:Seminar Room 1\, Newton Institute
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