J Austral Math Soc Ser B 31 pp472--483, 1990.
(Received 5 September, 1988; revised 28 February, 1989)
The basic problem in this paper is that of determining the geometry of an arbitrary doubly-connected region in R 2 together with an impedance condition on its inner boundary and another impedance condition on its outer boundary, from the complete knowledge of the eigenvalues {l j}¥j=1 for the two-dimensional Laplacian using the asymptotic expansion of the spectral function q(t) = å¥j=1exp(-tl j ) for small positive t.
Last Modified: Mon Jan 14 16:50:23 2002