On the spectrum of bounded immersions
arXiv:1211.6059 · doi:10.4310/jdg/1421415562
Abstract
In this paper, we investigate the relationship between the discreteness of the spectrum of a non-compact, extrinsically bounded submanifold $φ\colon M^m \ra N^n$ and the Hausdorff dimension of its limit set . In particular, we prove that if $φ\colon \!M^2 \ra D \subseteq \R^3$ is a minimal immersion into an open, bounded, strictly convex subset with -boundary, then has discrete spectrum provided that $\haus_Ψ(\limφ\cap D)=0$, where $\haus_Ψ$ is the generalized Hausdorff measure of order . Our theorem applies to a number of examples recently constructed by various authors in the light of N. Nadirashvili's discovery of complete, bounded minimal disks in , as well as to solutions of Plateau's problems, giving a fairly complete answer to a question posed by S.T. Yau in his Millenium Lectures. Suitable counter-examples show the sharpness of our results: in particular, we develop a simple criterion for the existence of essential spectrum which is suited for the techniques developed after Jorge-Xavier and Nadirashvili's examples.
24 pages. Submitted for publication