English

Eigenvalue estimates for the Laplacian on a metric tree

Spectral Theory 2016-07-28 v3 Mathematical Physics math.MP

Abstract

We provide explicit upper bounds for the eigenvalues of the Laplacian on a finite metric tree subject to standard vertex conditions. The results include estimates depending on the average length of the edges or the diameter. In particular, we establish a sharp upper bound for the spectral gap, i.e. the smallest positive eigenvalue, and show that equilateral star graphs are the unique maximizers of the spectral gap among all trees of a given average length.

Keywords

Cite

@article{arxiv.1602.03864,
  title  = {Eigenvalue estimates for the Laplacian on a metric tree},
  author = {Jonathan Rohleder},
  journal= {arXiv preprint arXiv:1602.03864},
  year   = {2016}
}

Comments

revised version; accepted for publication in Proc. Amer. Math. Soc

R2 v1 2026-06-22T12:48:37.855Z