An inverse problem of the wave equation for a general doubly connected region in R2 with a finite number of piecewise smooth Robin boundary conditions

摘要

The spectral distributionμ(t)=∑ω=1∞exp(−itEω1/2),where {Eω}ω=1∞ are the eigenvalues of the negative Laplacian−Δ=−∑k=12∂∂xk2in the (x1,x2)-plane, is studied for a variety of domains, where −∞