Intrinsic ergodicity of smooth interval maps

We generalize the technique of Markov Extension, introduced by F. Hofbauer 10] for piecewise monotonic maps, to arbitrary smooth interval maps. We also use A. M. Blokh’s 1] Spectral Decomposition, and a strengthened version of Y. Yomdin’s 23] and S. E. Newhouse’s 14] results on differentiable mappings and local entropy. In this way, we reduce the study ofC ^r interval maps to the consideration of a finite number of irreducible topological Markov chains, after discarding a small entropy set. For example, we show thatC ^∞ maps have the same properties, with respect to intrinsic ergodicity, as have piecewise monotonic maps.