© The London Mathematical Society
A Uniqueness Theorem in the Inverse Spectral Theory of a Certain Higher-Order Ordinary Differential Equation Using PaleyWiener Methods
Center for Mathematical Sciences Mathematics, Faculty of Science, University of Lund Box 118, SE-221 00 Lund, Sweden erik.andersson{at}math.lu.se
Received 19 September 2003. Revision received 19 February 2005.
The paper examines a higher-order ordinary differential equation of the form
where D = i(d/dx), and where the coefficients ajk, j,k
[0,m], with amm = 1, satisfy certain regularity conditions and are chosen so that the matrix (ajk) is hermitean. It is also assumed that m > 1. More precisely, it is proved, using PaleyWiener methods, that the corresponding spectral measure determines the equation up to conjugation by a function of modulus 1. The paper also discusses under which additional conditions the spectral measure uniquely determines the coefficients ajk, j,k
[0,m], j + k
2m, as well as b and the boundary conditions at 0 and at b (if any).