Decay of geometry for unimodal maps: The C2 case

We prove that a C2 unimodal interval map with critical order not greater than 2 has the decay of geometry property, by showing that all the cross-ratio estimates needed in the previous proof for the C3 case remain true. Supported by the National Basic Research Program of China (Grant No. 2006CB805900) and Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070358058)