Une note à propos du Jacobien de $n$ fonctions holomorphes à l'origine de ${\mathbb{C}}^n$

Abstract

Let $f_1,...,f_n$ be $n$ germs of holomorphic functions at the origin of ${\mathbb{C}}^n$ such that $f_i(0)=0$, $1\le i\le n$. We give a proof based on the J. Lipman's theory of residues via Hochschild Homology that the Jacobian of $f_1,...,f_n$ belongs to the ideal generated by $f_1,...,f_n$ belongs to the ideal generated by $f_1,...,f_n$ if and only if the dimension ot the germ of common zeos of $f_1,...,f_n$ is sttrictly positive. In fact we prove much more general results which are relatives versions of this result replacing the field $\mathbb{C}$ by convenient noetherian rings $\mathbf{A}$ (c.f. Th. 3.1 and Th. 3.3). We then show a Łojasiewicz inequality for the jacobian analogous to the classical one by S. Łojasiewicz for the gradient.