%0 Journal Article %T Somersaults on unstable islands %A Katrin Gelfert %J Mathematics %D 2014 %I arXiv %X We give extensions of Katok's horseshoe constructions, comment on related results, and provide a self-contained proof. We consider either a $C^{1+\alpha}$ diffeomorphism preserving a hyperbolic measure or a $C^1$ diffeomorphism preserving a hyperbolic measure whose support admits a dominated splitting. %U http://arxiv.org/abs/1411.7424v1