2 problems

Let $X\to \mathbb{A}^m$ be an $\mathbb{A}^n$-fibration, meaning that every fibre is isomorphic to $\mathbb{A}^n$. Dolgachev-Weisfeiler conjecture. The fibration is isomorphic to th…

Let $R$ be a ring and let $f_1,\ldots,f_m\in R^{[n]}$. A partial system of residual coordinates is a tuple for which the inclusion … is an affine fibration. A partial system of coo…