English

On eigenvalues of symmetric matrices with PSD principal submatrices

Algebraic Geometry 2021-03-30 v1 Optimization and Control

Abstract

We investigate convexity properties of the set of eigenvalue tuples of n×nn\times n real symmetric matrices, whose all k×kk\times k (where knk\leq n is fixed) minors are positive semidefinite. It is proven that the set λ(Sn,k)\lambda(\mathcal{S}^{n,k}) of eigenvalue vectors of all such matrices is star-shaped with respect to the nonnegative orthant R0n\mathbb{R}^n_{\geq 0} and not convex already when (n,k)=(4,2)(n,k)=(4,2).

Keywords

Cite

@article{arxiv.2103.15811,
  title  = {On eigenvalues of symmetric matrices with PSD principal submatrices},
  author = {Khazhgali Kozhasov},
  journal= {arXiv preprint arXiv:2103.15811},
  year   = {2021}
}
R2 v1 2026-06-24T00:39:40.605Z