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hal-00694765, version 1

Convex Relaxation for Combinatorial Penalties

Guillaume Obozinski (, http://www.di.ens.fr/~obozinski/) 12, Francis Bach (, http://www.di.ens.fr/~fbach/) 12

Abstract: In this paper, we propose an unifying view of several recently proposed structured sparsity-inducing norms. We consider the situation of a model simultaneously (a) penalized by a set- function de ned on the support of the unknown parameter vector which represents prior knowledge on supports, and (b) regularized in Lp-norm. We show that the natural combinatorial optimization problems obtained may be relaxed into convex optimization problems and introduce a notion, the lower combinatorial envelope of a set-function, that characterizes the tightness of our relaxations. We moreover establish links with norms based on latent representations including the latent group Lasso and block-coding, and with norms obtained from submodular functions.

  • 1:  SIERRA (INRIA Paris - Rocquencourt)
  • INRIA : PARIS - ROCQUENCOURT – Ecole normale supérieure de Paris - ENS Paris – CNRS : UMR8548
  • 2:  Laboratoire d'informatique de l'école normale supérieure (LIENS)
  • CNRS : UMR8548 – Ecole normale supérieure de Paris - ENS Paris
  • Domain : Statistics/Machine Learning
  • Keywords : sparsity – structured sparsity – submodular function – relaxation – set cover – set function – regularization – support recovery
  • Comment : 35 page
 
  • hal-00694765, version 1
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  • Submitted on: Sunday, 6 May 2012 15:44:49
  • Updated on: Sunday, 6 May 2012 21:54:36