The clarke generalized gradient for functions whose epigraph has positive reach
Document Type
Article
Publication Date
8-1-2013
Abstract
We consider the class of continuous functions that map an open set Ω ⊆ ℝn to ℝ with an epigraph having (locally) positive reach with an additional property. This class contains all finite convex and C11 1 functions, but also ones that are not necessarily Lipschitz continuous. We provide a representation formula for the Clarke generalized gradient of such functions using convex combinations and limits of gradients at differentiability points, thus offering an alternative to the well-known proximal normal formula by replacing a pointedness assumption by one of positive reach. Our proof consists of a detailed analysis of singularities using methods taken from both nonsmooth analysis and geometric measure theory, and is based on an induction argument. As an application, we prove for a particular class of Hamilton-Jacobi equations that an a.e. solution whose hypograph has positive reach and satisfies an additional property is indeed the unique viscosity solution. © 2013 INFORMS.
Publication Source (Journal or Book title)
Mathematics of Operations Research
First Page
451
Last Page
468
Recommended Citation
Colombo, G., Marigonda, A., & Wolenski, P. (2013). The clarke generalized gradient for functions whose epigraph has positive reach. Mathematics of Operations Research, 38 (3), 451-468. https://doi.org/10.1287/moor.1120.0580