posted on 2025-05-08, 14:23authored byJ. M. Borwein, Xianfu Wang
We construct, using Zahorski's Theorem, two everywhere differentiable real-valued Lipschitz functions differing by more than a constant but sharing the same Clarke subdifferential and the same approximate subdifferential.
First published in Proceedings of the American Mathematical Society in Vol. 125, No.3, pp. 807-813, 1997, published by the American Mathematical Society.