Smooth bijection and tangent spaces

differential-geometrysmooth-manifolds

Let $f:M\to N$ be a smooth bijection between manifolds with same dimension. Do we necessarily have

$$df_p(T_pM)=T_{f(p)}N.$$

I think it is probably not true. But I can't give a counterexample…

Best Answer

The map $f:\mathbb{R}\to\mathbb{R}$ given by $f:x\mapsto x^3$ is a smooth bijection but $df_0(T_0\mathbb{R}) = 0\neq T_{f(0)}\mathbb{R}$.