English

Helly-type theorem for eigenvectors

Metric Geometry 2017-02-14 v3 Combinatorics

Abstract

We prove that if any 3d/2\lfloor3d/2 \rfloor or fewer elements of a finite family of linear operators KdKd\mathbb K^d\to \mathbb K^d (K\mathbb K is an arbitrary field) have a common eigenvector then all operators in the family have a common eigenvector. Moreover, 3d/2\lfloor 3d/2\rfloor cannot be replaced by a smaller number. Also, we study the following problem, achieving partial results: prove that if any l=O(d)l=O(d) or fewer elements of a finite family of linear operators KdKd\mathbb K^d\to \mathbb K^d have a common non-trivial invariant subspace then all operators in the family have a common non-trivial invariant subspace.

Keywords

Cite

@article{arxiv.1611.03251,
  title  = {Helly-type theorem for eigenvectors},
  author = {Alexandr Polyanskii},
  journal= {arXiv preprint arXiv:1611.03251},
  year   = {2017}
}

Comments

v2: 6 pages, corrections are made in Section 2 v3: 6 pages, corrections are made in the proof of Lemma 1 (Section 3)

R2 v1 2026-06-22T16:48:01.924Z