We consider the generalised Krein-Feller operator $\Delta_{ \nu, \mu} $ with respect to compactly supported Borel probability measures $\mu$ and $\nu$ with the natural restrictions that $\mu$ is atomless, the supp$(\nu)\subseteq$supp$(\mu)$ and the atoms of $\nu $ are embedded in the supp$(\mu)$. We show that the solutions of the eigenvalue problem for $\Delta_{ \nu, \mu} $ can be transferred to the corresponding problem for the classical Krein-Feller operator $\Delta_{ \nu \circ F_{ \mu}^{ -1}, \Lambda}$ with respect to the Lebesgue measure $\Lambda$ via an isometric isomorphism determined by the distribution function $F_\mu$ of $\mu$. In this way, we obtain a new characterisation of the upper spectral dimension and consolidate many known results on the spectral asymptotics of Krein-Feller operators. We also recover known properties of and connections to generalised gap diffusions associated to these operators.
Categories: math.FA math.PR math.SP