"Hamilton and Moitra's 'Paulsen problem made simple'"

Abstract: The Paulsen problem asks for quantitative bounds for the distance between Parseval frames and frames which are "nearly" Parseval frames.  One version of this problem was solved recently by Kwok, Lau, Lee, Ramachandran.  An even more recent work of Hamilton and Moitra gives a better estimate and a simpler proof.  We shall discuss this proof which utilizes ideas from operator scaling and the Brascamp-Lieb inequality as well as the concept of radial isotropic position.  

Host: John McCarthy