A Hölder-type inequality for the $C^0$ distance and Anosov-Katok pseudo-rotations

We prove a Hölder-type inequality for Hamiltonian diffeomorphisms relating the $C^0$ norm, the $C^0$ norm of the derivative, and the Hofer/spectral norm. We obtain as a consequence that sufficiently fast convergence in Hofer/spectral metric forces $C^0$ convergence. The second theme of our paper is the study of pseudo-rotations that arise from the Anosov-Katok method. As an application of our Hölder-type inequality, we prove a $C^0$ rigidity result for such pseudo-rotations.