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Title:
Efficient non-convex polynomial optimization and the sum-of-squares hierarchy

Speaker:
David Steurer

Abstract:
The sum-of-squares (SOS) hierarchy (due to Shor'85, Parrilo'00, and Lasserre'00) is a widely-studied meta-algorithm for (non-convex) polynomial optimization that has its roots in Hilbert's 17th problem about non-negative polynomials. SOS plays an increasingly important role in theoretical computer science because it affords a new and unifying perspective on the field's most basic question: What's the best possible polynomial-time algorithm for a given computational problem? For a wide range of problems, SOS generalizes the best-known polynomial-time algorithms and achieves plausibly optimal guarantees. I will explain key concepts behind SOS that turn out to be constructive versions of the notions of proof and probability. Then, I will show that SOS gives significantly better guarantees than previous algorithms for two basic non-convex optimization problem: the sparse coding problem from machine learning and the best-separable-state problem from quantum information theory. Based on joint works with Boaz Barak, Pravesh Kothari, Tengyu Ma, and Jonathan Shi.

Link:
https://www.ias.edu/video/membsem/2017/0320-DavidSteurer