Title
The Power of Sum-of-Squares for Detecting Hidden Structures
Abstract
We study planted problems-finding hidden structures in random noisy inputs-through the lens of the sum-of-squares semidefinite programming hierarchy (SoS). This family of powerful semidefinite programs has recently yielded many new algorithms for planted problems, often achieving the best known polynomial-time guarantees in terms of accuracy of recovered solutions and robustness to noise. One theme in recent work is the design of spectral algorithms which match the guarantees of SoS algorithms for planted problems. Classical spectral algorithms are often unable to accomplish this: the twist in these new spectral algorithms is the use of spectral structure of matrices whose entries are low-degree polynomials of the input variables. We prove that for a wide class of planted problems, including refuting random constraint satisfaction problems, tensor and sparse PCA, densest-ksubgraph, community detection in stochastic block models, planted clique, and others, eigenvalues of degree-d matrix polynomials are as powerful as SoS semidefinite programs of degree d. For such problems it is therefore always possible to match the guarantees of SoS without solving a large semidefinite program. Using related ideas on SoS algorithms and lowdegree matrix polynomials (and inspired by recent work on SoS and the planted clique problem [BHK <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> 16]), we prove a new SoS lower bound for the tensor PCA problem.
Year
DOI
Venue
2017
10.1109/FOCS.2017.72
2017 IEEE 58th Annual Symposium on Foundations of Computer Science (FOCS)
Keywords
DocType
Volume
sum of squares,semidefinite programming,average-case algorithms,average-case hardness,spectral algorithms
Journal
abs/1710.05017
ISSN
ISBN
Citations 
0272-5428
978-1-5386-3465-3
6
PageRank 
References 
Authors
0.41
26
6
Name
Order
Citations
PageRank
Samuel Hopkins1889.47
Pravesh Kothari220322.17
Aaron Potechin3637.81
Prasad Raghavendra4101350.58
Tselil Schramm5788.82
David Steurer693444.91