| Article ID: | iaor2013173 |
| Volume: | 49 |
| Issue: | 3 |
| Start Page Number: | 505 |
| End Page Number: | 519 |
| Publication Date: | Mar 2011 |
| Journal: | Journal of Global Optimization |
| Authors: | Penot Jean-Paul |
We provide a criterion giving a formula for the directional (or contingent) subdifferential of the difference of two convex functions. We even extend it to the difference of two approximately starshaped functions. Our analysis relies on a notion of approximate monotonicity for operators which is much less demanding than the usual one.