3 problems

Let $Z(\lambda)$ denote the marginal likelihood for a regularized linear regression model, with ridge, lasso, and group lasso corresponding to their respective regularizers. Quasic…

Zero-matrix quasiconcavity conjecture. Burkholder functions are quasiconcave at the zero matrix.

For $p\geqslant n/2$ and $\lambda\geqslant\left|1-n/p\right|$, define the Burkholder matrix function … The source also defines the planar Burkholder function…