Work

Maximisers for the second Neumann eigenvalue of annuli in two-dimensional space forms

Year: 2026
Type: preprint
Abstract: We prove a sharp Szegö-Weinberger-type inequality for balanced doubly connected domains in $\mathbb S^2$, $\mathbb R^2$ and $\mathbb H^2$. More precisely, the first positive Neumann eigenvalue is bounded above by that of the corresponding rotationally symmetric annulus, determined by the area of the domain and the area of the smallest component of the complement. Equality holds only for the rotationally symmetric annulus. We also show that the balancing assumption is essential: if we drop it, the inequality fails in general.
Language: English
Open Access status: green
OpenAlex ID: W7220979413
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