E. M. E. ZAYED
The trace of the wave kernel
are the eigenvalues of the negative Laplacian
in the (
x1,
x2,
x3)-space, is studied for a variety of bounded domains, where -∞ < t < ∞ and
. The dependence of
û(
t) on the connectivity of bounded domains and the Dirichlet, Neumann and Robin boundary conditions are analyzed. Particular attention is given for a multi-connected vibrating membrane Ω in
R3 surrounded by simply connected bounded domains Ω
j with smooth bounding surfaces
Sj (
j = 1, . . .,
n), where a finite number of piecewise smooth Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components
(
i = 1+
kj-1 , . . .,
kj ) of the bounding surfaces
S j are considered, such that
, where
k0 = 0. The basic problem is to extract information on the geometry Ω by using the wave equation approach from a complete knowledge of its eigenvalues. Some geometrical quantities of Ω (e.g. the volume, the surface area, the mean curvuture and the Gaussian curvature) are determined from the asymptotic expansion of
û (
t) for small |
t|.