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Enumerative Lattice Algorithms in Any Norm via M-Ellipsoid Coverings

Algebra & Discrete Mathematics

Speaker: Daniel Dadush, Georgia Tech
Location: 2112 MSB
Start time: Fri, Oct 28 2011, 2:10PM

We give a novel algorithm for enumerating lattice points in any convex body, and give applications to several classic lattice problems, including the Shortest and Closest Vector Problems (SVP and CVP, respectively) and Integer Programming (IP). Our enumeration technique relies on a classical concept from asymptotic convex geometry known as the M-ellipsoid, and uses as a crucial subroutine the recent algorithm of Micciancio and Voulgaris (STOC 2010) for lattice problems in the l_2 norm. As a main technical contribution, which may be of independent interest, we build on the techniques of Klartag (Geometric and Functional Analysis, 2006) to give an expected 2^{O(n)}-time algorithm for computing an M-ellipsoid for any n-dimensional convex body.