Abstract
The first nonzero eigenvalue of the Neumann Laplacian is shown to be minimal for the degenerate acute isosceles triangle, among all triangles of given diameter. Hence an optimal Poincaré inequality for triangles is derived.The proof relies on symmetry of the Neumann fundamental mode for isosceles triangles with aperture less than π/3. Antisymmetry is proved for apertures greater than π/3 copy; 2010 Elsevier Inc.
Original language | English (US) |
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Pages (from-to) | 118-135 |
Number of pages | 18 |
Journal | Journal of Differential Equations |
Volume | 249 |
Issue number | 1 |
DOIs | |
State | Published - Jul 2010 |
Keywords
- Free membrane
- Isodiametric
- Isoperimetric
- Poincaré inequality
ASJC Scopus subject areas
- Analysis
- Applied Mathematics