2018/06/04 by Lim, Lek-Heng, Sepulchre, Rodolphe, Ye, Ke · 2 citations
#15A18 #15B48 #51K99 #53C25 #FOS: Mathematics #Numerical Analysis (math.NA)
paper · doi:10.48550/arxiv.1806.01428
We show how the Riemannian distance on \mathbbSn++, the cone of n× n real symmetric or complex Hermitian positive definite matrices, may be used to naturally define a distance between two such matrices of different dimensions. Given that \mathbbSn++ also parameterizes n-dimensional ellipsoids, and inner products on ℝn, n × n covariance matrices of nondegenerate probability distributions, this gives us a natural way to define a geometric distance between a pair of such objects of different dimensions.