Integral curves and Jacobian Conjecture
Jean-Yves Charbonnel
TL;DR
The paper tackles the Jacobian Conjecture by focusing on étale polynomial endomorphisms of $\mathbb{C}^n$ of the form $\Phi(x)=x+F^{(3)}(x)$ and leveraging Drużkowski's reduction. It develops a semialgebraic framework and a vector-field approach, introducing the integral curve flow $X_x(y)=\Phi'(y)^{-1}(x)$ and showing that maximal integral curves yield a polynomial inverse to $\Phi$, proving $\Phi$ is a polynomial automorphism when étale. Through an analysis of algebraic curves $\Gamma_x$ and their étale coverings, it establishes finiteness and rigidity properties that force the global invertibility of $\Phi$, culminating in the main theorem that étale polynomial endomorphisms are automorphisms. Consequently, the Jacobian Conjecture holds in this setting, with implications extending to automorphism results for Weyl algebras over characteristic-zero fields.
Abstract
In this note, we are interested in the Jacobian Conjecture. Following the results of L.M.~Dru$\dot{\rm z}$kowski, we consider some vector fields depending on a certain étale polynomial map. From results of semialgebraic geometry with the consideration of some integral curves of these vector fields, we deduce that an étale polynomial endomorphism is a polynomial automorphism.
