Titchmarsh’s asymptotic formula for periodic eigenvalues and an extension to the p-Laplacian

An asymptotic formula for periodic eigenvalues, due to Titchmarsh, is taken to a higher degree of accuracy using a Prüfer transformation method, not depending on Floquet theory. With the idea of the rotation number, this method is then extended to the p-Laplacian. © 2007 Elsevier Inc. All rights reserved