Inverse spectral problems for differential equations on the half-line with turning points

Boundary value problems for second-order differential equations on the half-line having an arbitrary number of turning points are investigated. We establish properties of the spectra, prove an expansion theorem, and study inverse problems of recovering the boundary value problem from given spectral characteristics. For these inverse problems we prove uniqueness theorems and provide a procedure for constructing the solution. (C) 1999 Academic Press.