Global transformations preserving spectral data

Hiroshi Isozaki, Evgeny L. Korotyaev

We show the existence of a real analytic isomorphism between a space of impedance function $\rho$ of the Sturm-Liouville problem $-{\rho }^{-2}({\rho }^2{f}^{\prime }{)}^{\prime }+uf$ on $(0,1)$, where $u$ is a fun…