Nonsmooth convex-concave saddle point problems with cardinality penalties

Fuente: arXiv
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Main Authors: Bian, Wei, Chen, Xiaojun
Format: Preprint
Published: 2024
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_version_ 1866929289304211456
author Bian, Wei
Chen, Xiaojun
author_facet Bian, Wei
Chen, Xiaojun
contents In this paper, we focus on a class of convexly constrained nonsmooth convex-concave saddle point problems with cardinality penalties. Although such nonsmooth nonconvex-nonconcave and discontinuous min-max problems may not have a saddle point, we show that they have a local saddle point and a global minimax point, and some local saddle points have the lower bound properties. We define a class of strong local saddle points based on the lower bound properties for stability of variable selection. Moreover, we give a framework to construct continuous relaxations of the discontinuous min-max problems based on the convolution, such that they have the same saddle points with the original problem. We also establish the relations between the continuous relaxation problems and the original problems regarding local saddle points, global minimax points, local minimax points and stationary points. Finally, we illustrate our results with distributionally robust sparse convex regression, sparse robust bond portfolio construction and sparse convex-concave logistic regression saddle point problems.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17535
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nonsmooth convex-concave saddle point problems with cardinality penalties
Bian, Wei
Chen, Xiaojun
Optimization and Control
90C46, 49K35, 90C30, 65K05
In this paper, we focus on a class of convexly constrained nonsmooth convex-concave saddle point problems with cardinality penalties. Although such nonsmooth nonconvex-nonconcave and discontinuous min-max problems may not have a saddle point, we show that they have a local saddle point and a global minimax point, and some local saddle points have the lower bound properties. We define a class of strong local saddle points based on the lower bound properties for stability of variable selection. Moreover, we give a framework to construct continuous relaxations of the discontinuous min-max problems based on the convolution, such that they have the same saddle points with the original problem. We also establish the relations between the continuous relaxation problems and the original problems regarding local saddle points, global minimax points, local minimax points and stationary points. Finally, we illustrate our results with distributionally robust sparse convex regression, sparse robust bond portfolio construction and sparse convex-concave logistic regression saddle point problems.
title Nonsmooth convex-concave saddle point problems with cardinality penalties
topic Optimization and Control
90C46, 49K35, 90C30, 65K05
url https://arxiv.org/abs/2403.17535