Date: Nov 7, 2012 10:30 AM
Author: Kaba
Subject: Uniqueness of Q

Hi,

Let Q, U, D, V in R^{n x n}, where Q^T Q = U^T U = V^T V = I, and D is 
non-negative diagonal. Consider the equation

     Q^T UDV^T = VDU^T Q.

One solution to this equation is Q = UV^T.

Prove or disprove: this solution is unique.

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