### Refine

- Sensitivity in the Rigid Punch Problem (1991)
- The rigid punch problem, a certain contact problem, leads to a noncoercive variational inequality. We show that its solution admits a directional derivative with respect to the data.

- Sensitivity in the Rigid Punch Problem (1991)
- The rigid punch problem, a certain contact problem, leads to a noncoercive variational inequality. We show that its solution admits a directional derivative with respect to the data.