Title
NP-Hardness of Approximately Solving Linear Equations Over Reals
Abstract
In this paper, we consider the problem of approximately solving a system of homogeneous linear equations over reals, where each equation contains at most three variables. Since the all-zero assignment always satisfies all the equations exactly, we restrict the assignments to be "non-trivial". Here is an informal statement of our result: it is NP-hard to distinguish whether there is a non-trivial assignment that satisfies 1-δ fraction of the equations or every non-trivial assignment fails to satisfy a constant fraction of the equations with a "margin" of Ω(√δ). We develop linearity and dictatorship testing procedures for functions f: Rn - R over a Gaussian space, which could be of independent interest. We believe that studying the complexity of linear equations over reals, apart from being a natural pursuit, can lead to progress on the Unique Games Conjecture.
Year
DOI
Venue
2013
10.1145/1993636.1993692
Electronic Colloquium on Computational Complexity
Keywords
DocType
Volume
independent interest,unique games conjecture,gaussian space,constant fraction,linear equation,informal statement,non-trivial assignment,all-zero assignment,dictatorship testing procedure,homogeneous linear equation,linear equations,hardness of approximation
Journal
42
Issue
Citations 
PageRank 
3
6
0.48
References 
Authors
15
2
Name
Order
Citations
PageRank
Subhash Khot12064112.51
Dana Moshkovitz236819.14