Operator-Lipschitz functions in Schatten-von Neumann classes

Abstract

This paper resolves a number of conjectures in the perturbation theory of linear operators. Namely, we prove that every Lipschitz function is operator Lipschitz in the Schatten-von Neumann ideals $S^\alpha$, $1 < \alpha < \infty$. The negative result for $S^\alpha$, $\alpha = 1, \infty$ was earlier established by Yu. Farforovskaya in 1972.