An extension of Krein’s inverse spectral theorem to strings with nonreflecting left boundaries
An extension of Krein’s inverse spectral theorem to strings with nonreflecting left boundaries
Krein’s inverse spectral theorem describes the spectral measures τ of the differential operators DmDx with boundary condition f_′(0)=0, if m runs through all nondecreasing functions on [0, ∞). This result will be extended to boundary conditions of the type af_′(0)−f(0)=0 (a ε [0, ∞)).Other conditions as in Krein’s theorem appear.