Title
Dispersion of mass and the complexity of randomized geometric algorithms
Abstract
How much can randomness help computation? Motivated by this general question and by volume computation, one of the few instances where randomness provably helps, we analyze a notion of dispersion and connect it to asymptotic convex geometry. We obtain a nearly quadratic lower bound on the complexity of randomized volume algorithms for convex bodies in \mathbb{R}^n (the current best algorithm has complexity roughly n^4, conjectured to be n^3). Our main tools, dispersion of random determinants and dispersion of the length of a random point from a convex body, are of independent interest and applicable more generally; in particular, the latter is closely related to the variance hypothesis from convex geometry. This geometric dispersion also leads to lower bounds for matrix problems and property testing.
Year
DOI
Venue
2006
10.1016/j.aim.2008.06.004
Electronic Colloquium on Computational Complexity
Keywords
DocType
Volume
lower bounds,variance hypothesis,dispersion of mass,randomized algorithms,determinant computation,volume computation,property testing,convex body,convex geometry,lower bound,randomized algorithm
Journal
219
Issue
ISSN
ISBN
3
Advances in Mathematics
0-7695-2720-5
Citations 
PageRank 
References 
5
0.67
15
Authors
2
Name
Order
Citations
PageRank
Luis Rademacher126921.60
Santosh Vempala23546523.21