Quarterly of Applied Mathematics

Nodal and other properties of the second eigenfunction of the Laplacian in the plane

Author(s): Richard L. Liboff
Journal: Quart. Appl. Math. 63 (2005), 673-679.
MSC (2000): Primary 65Nxx, 35Jxx
Posted: August 3, 2005
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Abstract: Rules are established for the intersection of nodals at a boundary in the plane relevant to the second eigenfunction of the Laplacian. Employing these results together with regularity theorems related to odd reflection of solutions of the Helmholtz equation, as well as a variation of C.S. Lin's analysis, the following theorem is revisited: The nodal curve of the second eigenstate of the Laplacian for bounded convex domains in the plane, with Dirichlet boundary conditions, is a simple curve that intersects the boundary in two distinct points. Application is made to the regular convex polygons with $C_{n}, n \geq 2$ , symmetry and to convex billiards with smooth boundaries.

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Richard L. Liboff
Affiliation: Schools of Electrical Engineering and Applied Physics, and Center for Applied Math, Cornell University, Ithaca, New York 14853-5401
Email: richaard@ece.cornell.edu

PII: S0033-569X-05-00975-3
Received by editor(s): January 11, 2005
Received by editor(s) in revised form: February 24, 2005
Posted: August 3, 2005
Additional Notes: Fruitful discussions on these topics with my colleagues Alfred Schatz, Bradley Minch, Mason Porter and Sidney Leibovich are gratefully acknowledged. I am particularly indebted to Lawrence Payne for sharing his expertise with me in this study.
Copyright of article: Copyright 2005, Brown University

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