Non-uniformly expanding dynamics in maps with singularities and criticalities (Q1594560)

A certain dynamical aspect of a subtle class of one-parameter families of interval maps is studied in this work. The maps are odd functions with a discontinuity at the origin, two critical points, \(C^1\) outside the origin and \(C^2\) outside the origin and the critical points. They enjoy a concavity property outside the origin. Also, there are conditions on expandicity and periodicity inside a family. The rather technical result implies the existence of a parameter subset of positive Lebesgues measure for whose members the maps have positive Lyapunov exponent and which contains a dynamically important density point. -- The motivation for studying these families of maps is their relevance in the context of the 3-dimensional Lorenz system.