English

A convex, finite and lower semicontinuous function with empty subdifferential

Optimization and Control 2024-09-30 v1

Abstract

We give an example of a convex, finite and lower semicontinuous function whose subdifferential is everywhere empty. This is possible since the function is defined on an incomplete normed space. The function serves as a universal counterexample to various statements in convex analysis in which completeness is required.

Keywords

Cite

@article{arxiv.2409.18650,
  title  = {A convex, finite and lower semicontinuous function with empty subdifferential},
  author = {Gerd Wachsmuth},
  journal= {arXiv preprint arXiv:2409.18650},
  year   = {2024}
}
R2 v1 2026-06-28T18:59:23.186Z