Figure 2:

A. Simulation of Wald interval as a function of $\lambda$. B. First-order and second-order derivatives of the curve. The solid line represents ${\lambda }_0$, the fine dotted line represents ${\lambda }_{CV}$, and the thick dotted line represents ${\lambda }_{\text{plateau}}$. (Reproduced figure Cai and van der Laan [2020]).