A Note on Residual Variables of an Affine Fibration

Abstract

In a recent paper [El 13], M.E. Kahoui has shown that if $R$ is a polynomial ring over $\mathbb{C}$, $A$ an ${\mathbb{A}}^3$-fibration over $R$, and $W$ a residual variable of $A$ then $A$ is stably polynomial over $R[W]$. In this article we show that the above result holds over any Noetherian domain $R$ provided the module of differentials ${\Omega }_R(A)$ of the affine fibration $A$ (which is necessarily a projective $A$-module by a theorem of Asanuma) is a stably free $A$-module.

6 pages

Cited by in corpus (2)

• On cancellation of variables of the form $b{T}^n-a$ over affine normal domains
• Rank and rigidity of locally nilpotent derivations of affine fibrations