English

Robin spectrum: two disks maximize the third eigenvalue

Spectral Theory 2019-08-01 v1 Analysis of PDEs

Abstract

The third eigenvalue of the Robin Laplacian on a simply-connected planar domain of given area is bounded above by the third eigenvalue of a disjoint union of two disks, provided the Robin parameter lies in a certain range and is scaled in each case by the length of the boundary. Equality is achieved when the domain degenerates suitably to the two disks.

Keywords

Cite

@article{arxiv.1907.13173,
  title  = {Robin spectrum: two disks maximize the third eigenvalue},
  author = {Alexandre Girouard and Richard S. Laugesen},
  journal= {arXiv preprint arXiv:1907.13173},
  year   = {2019}
}

Comments

32 pages, 8 figures

R2 v1 2026-06-23T10:35:20.746Z