C-1 density of stable ergodicity

We prove a C-1 version of a conjecture by Pugh and Shub: among partially hyperbolic volume-preserving C-r diffeomorphisms, r > 1, the stably ergodic ones are C-1-dense. To establish these results, we develop new perturbation tools for the C-1 topology: linearization of horseshoes while preserving entropy, and creation of "superblenders" from hyperbolic sets with large entropy. (C) 2020 Published by Elsevier Inc.