English

On Jordan angles and triangle inequality in Grassmannian

Differential Geometry 2013-01-15 v1 Metric Geometry Spectral Theory

Abstract

We obtain the following version of Lidskii theorem. Let L, M, N be p-dimensional subspaces in R^n. Let \psi_j be the angles between L and M, let \phi_j be the angles between M and N, and let \theta_j be the angles between L and N. Consider the orbit of the vector \psi with respect to permutations of coordinates and inversions of axises. Let Z be the convex hull of this orbit. Then \theta is an element of the polyhedron \phi + Z. We discuss similar theorems for other symmetric spaces. We obtain formula for geodesic distance for any invariant Finsler metrics on a classical Riemannian symmetric space.

Keywords

Cite

@article{arxiv.math/0005059,
  title  = {On Jordan angles and triangle inequality in Grassmannian},
  author = {Yurii A. Neretin},
  journal= {arXiv preprint arXiv:math/0005059},
  year   = {2013}
}

Comments

12 pages

R2 v1 2026-07-22T16:32:33.693Z