A 4-steps elementary proof of existence of Lagrange multipliers Published: 2025/10/14 Gabriel HaeserDaiana O. SantosCategories Constrained Nonlinear Optimization, Nonlinear Optimization Tags nonlinear programming Short URL: https://optimization-online.org/?p=32215 We present a simplified proof of Lagrange’s theorem using only elementary properties of sets and sequences. ArticleDownload View PDF