2018

On Representer Theorems and Convex Regularization

Boyer, Claire, Chambolle, Antonin, De Castro, Yohann et al.

Understand

We establish a general principle which states that regularizing an inverse problem with a convex function yields solutions which are convex combinations of a small number of atoms.

  • These atoms are identified with the extreme points and elements of the extreme rays of the regularizer level sets.
  • An extension to a broader class of quasi-convex regularizers is also discussed.
  • As a side result, we characterize the minimizers of the total gradient variation, which was still an unresolved problem.

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