Figure 1.

Unit balls of J_λ,I,W norm for different λ. Weights w₁ and w₂ are equal to $\sqrt{2}$ and 1. The edges in (a) correspond to the same weighted group effects, i.e. $w_1\sqrt{{\beta }_1^2+{\beta }_2^2}=w_2\mid {\beta }_2\mid =0.5$; all edges in (b) contain at least one zero group effect (gLASSO); in (c) both types of edges appear.