Robust transitivity for endomorphisms admitting critical points
  We address the problem of giving necessary and sufficient conditions in order to have robustly transitive endomorphisms admitting persistent critical sets. We exhibit different type of open examples of robustly transitive maps in any isotopic class of endomorphisms acting on the two dimensional torus admitting persistent critical points. We also provide some necessary condition for robust transitivity in this setting. 
Jorge Iglesias, Cristina Lizana and Aldo Portela
math.DS