We prove that if a lattice basis is nearly orthogonal (the angle between any basis vector and the linear subspace spanned by the other basis vectors is a least radians), then the basis is nearly KZ-reduced for some ordering of the basis vectors. It follows that a KZ-reduced basis can be obtained from a nearly orthogonal basis in polynomial time. We also show that if a nearly orthogonal lattice basis has nearly equal vector lengths (they are within a certain constant factor of one another), then the basis is Minkowski reduced. We use this result to show that m i.i.d. random vectors drawn from a uniform distribution over the unit ball in form a Minkowski-reduced basis of the lattice generated by the vectors almost surely as n tends to infinity, if for a constant . This result extends a result of Donaldson (1979) who proved the above property for fixed m as n tends to infinity.

By:* Sanjeeb Dash; Ramesh Neelamani; Gregory B. Sorkin*

Published in: RC24696 in 2008

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