Recovery of sums of sparse and dense signals by incorporating graphical structure among predictors

Abstract

With the abundance of high‐dimensional data, sparse regularization techniques are very popular in practice because of the built‐in sparsity of their corresponding estimators. However, the success of sparse methods heavily relies on the assumption of sparsity in the underlying model. For models where the sparsity assumption fails, the performance of these sparse methods can be unsatisfactory and misleading. In this article, we consider the perturbed linear model, where the signal is given by the sum of sparse and dense signals. We propose a new penalization‐based method, called Gava, to tackle this kind of signal by making use of a graphical structure among model predictors. The proposed Gava method covers several existing methods as special cases. Our numerical examples and theoretical studies demonstrate the effectiveness of the proposed Gava for estimation and prediction.