English

A self-contained proof of the Alt-Caffarelli-Friedman monotonicity formula

Analysis of PDEs 2026-05-22 v2

Abstract

The Alt-Caffarelli-Friedman monotonicity formula is a cornerstone in the theory of free boundary problems. In this note we provide a self-contained proof of this result. To prove the main stepping stone, namely the Friedland-Hayman inequality, we exploit a useful convexity property.

Keywords

Cite

@article{arxiv.2506.13473,
  title  = {A self-contained proof of the Alt-Caffarelli-Friedman monotonicity formula},
  author = {Emanuele Salato},
  journal= {arXiv preprint arXiv:2506.13473},
  year   = {2026}
}