English

The Implicit Function Theorem when the matrix $\frac{\partial F}{\partial y}(x,y)$ is only continuous at the base point

Classical Analysis and ODEs 2022-02-15 v2

Abstract

This article presents an elementary proof of the Implicit Function Theorem for differentiable maps F(x,y), defined on a finite-dimensional Euclidean space, with Fy(x,y)\frac{\partial F}{\partial y}(x,y) only continuous at the base point. In the case of a single scalar equation this continuity hypothesis is not required. The Inverse Function Theorem is also shown. The proofs rely on the mean-value and the intermediate-value theorems and Darboux's property (the intermediate-value property for derivatives). These proofs avoid compactness arguments, fixed-point theorems, and integration theory.

Keywords

Cite

@article{arxiv.1312.2445,
  title  = {The Implicit Function Theorem when the matrix $\frac{\partial F}{\partial y}(x,y)$ is only continuous at the base point},
  author = {Oswaldo R. B. de Oliveira},
  journal= {arXiv preprint arXiv:1312.2445},
  year   = {2022}
}

Comments

9 pages - new version with 10 pages, two added references on section 1, corrected grammar

R2 v1 2026-06-22T02:23:45.098Z