Higher dimensional inverse problem of the wave equation for a bounded domain with mixed boundary conditions

This paper is an extension to a recent work of Zayed and Abdel-Halim (Chaos, Solitons & Fractals, to appear; Acta Math Sci, to appear). The spectral function , where {EJ}J=1∞ are the eigenvalues of the negative Laplacian in R3, is studied for a variety of domain, where −∞