2010/12/30 by Yves Colin de Verdìère, Yves Colin de Verdière, de Verdière, Yves Colin +4
Mathematics · #35P20 #35R30 #Analysis of PDEs (math.AP) #Analytic and geometric function theory #FOS: Mathematics #Mathematical functions and polynomials #Spectral Theory in Mathematical Physics #math.AP #msc:35P20 #msc:35R30
paper · pdf · doi:10.48550/arxiv.1101.0099
24 pages
arxiv created 2010/12/30 · openalex publication_date 2010/12/30 · arxiv updated 2011/01/04 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Let -λj be the eigenvalues of the Laplace operator on the unit disk with Dirichlet conditions. The distribution h(t) = ∑j ei√λj t is the trace of the solution operator of the wave equation on the disk. It is well known that h has isolated singularities at the lengths of the reflecting geodesics. In particular, h is singular at tk, the perimeter of the regular inscribed polygon with k sides. Evidently, tk < 2π, the perimeter of the circle, and tk tends to 2π. In this paper, we show that h(t) is infinitely differentiable as t tends to 2π from the right.