Let \(f\in C^\infty (S^n)\) be a smooth function and let \(x_1,x_2\in S^n\) be two points such that \(f(x_1)<0<f(x_2)\). Let \(\omega \) be a smooth nonvanishing \(n\)-form. Then there is a diffeomorphism \(\varphi :S^n\to S^n\) such that \[ \int _{S^n}(\varphi ^*f)\,\omega =0. \]
II. Ten point questions.